Systems, devices, and methods for providing electrotherapy

ABSTRACT

Systems, devices and methods for providing a pressurized fluid for facilitating conductive gel release prior to providing cardiac therapy to a patient are disclosed. A first system can include a chemical reaction chamber including a first chemical and a second chemical isolated from each other by a mechanical barrier. The mechanical barrier is configured to be compromised upon receiving a signal from an electrotherapy device controller such that the first chemical and second chemical come into contact to produce a sufficient amount of pressurized fluid. An alternative system can include a pressure source comprising a reservoir containing a pressurized fluid. The pressure source can also include at least one release mechanism configured to cause a release of the pressurized fluid from the reservoir to an exit port of the pressure source when a wearable medical device is preparing to deliver a therapeutic shock to a patient.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. § 119(e) ofU.S. provisional application Ser. No. 62/414,232 filed on Oct. 28, 2016,the disclosure of which is hereby expressly incorporated by reference inits entirety.

BACKGROUND

The present disclosure is directed to medical therapy systems, and moreparticularly, to electrode systems such as therapy electrodes includingpressure sources.

Cardiac arrest and other cardiac health ailments are a major cause ofdeath worldwide. Various resuscitation efforts aim to maintain thebody's circulatory and respiratory systems during cardiac arrest in anattempt to save the life of the victim. The sooner these resuscitationefforts begin, the better the victim's chances of survival. Theseefforts are expensive and have a limited success rate, and cardiacarrest, among other conditions, continues to claim the lives of victims.

To protect against cardiac arrest and other cardiac health ailments,some at-risk subjects may use a non-invasive bodily-attached ambulatorymedical monitoring and treatment device, such as the LifeVest® wearablecardioverter defibrillator available from ZOLL Medical Corporation. Toremain protected, the subject wears the device nearly continuously whilegoing about their normal daily activities, while awake, and whileasleep.

Such medical devices work by providing one or more shocks to a patient.Prior to delivering the one or more shocks, a conductive gel deploymentdevice can release a conductive gel about a conductive surface of atherapy electrode such that the one or more shocks can be directed fromthe therapy electrode to the patient's skin.

SUMMARY

In some implementations, an electrode for providing electrotherapy froman ambulatory electrotherapy device comprising: at least one reservoircomprising a conductive gel; at least one pressure source comprising achemical reaction chamber comprising a first chemical and a secondchemical isolated from each other by a mechanical barrier, wherein themechanical barrier is configured to be compromised upon receiving asignal from an electrotherapy device controller, and wherein the firstchemical and second chemical come into contact when the mechanicalbarrier is compromised to produce a sufficient amount of fluid togenerate a sufficient pressure within the chamber, is provided.

In some implementations, the electrode further comprises at least onerelease mechanism configured to compromise the mechanical barrier,thereby releasing the second chemical such that the second chemicalreacts with the first chemical.

In some implementations, the at least one release mechanism comprises aheat producing device.

In some implementations, the at least one release mechanism comprises amechanical device configured to facilitate movement of at least one ofthe first chemical and the second chemical.

In some implementations, the mechanical barrier comprises at least onemeltable membrane configured to isolate the first chemical from thesecond chemical.

In some implementations, the electrode further comprises a resistivewire in contact with the at least one meltable membrane and configuredto produce a heat to melt the at least one meltable membrane.

In some implementations, the electrode further comprises an exit portconnected to a fluid channel, wherein the exit port is configured todirect the pressurized fluid into the fluid channel.

In some implementations, a pressure level of the produced fluid isbetween 15 psi and 40 psi.

In some implementations, a system for providing therapy to a patient,the system comprising: a garment; a monitor configured to monitor atleast a physiological parameter of a patient; and a plurality of therapyelectrodes operably connected to the monitor and disposed in thegarment, each of the plurality of therapy electrodes comprising apressure source for providing a pressurized fluid to facilitateconductive gel deployment in a wearable medical device, the pressuresource comprising a chemical reaction chamber comprising a firstchemical and a second chemical isolated from each other by a mechanicalbarrier, wherein the mechanical barrier is configured to be compromisedupon receiving a signal from an electrotherapy device controller, andwherein the first chemical and second chemical come into contact whenthe mechanical barrier is compromised to produce a sufficient amount offluid to generate a sufficient pressure within the chamber, is provided.

In some implementations, each of the plurality of therapy electrodesfurther comprise at least one conductive surface configured to deliver atherapeutic shock.

In some implementations, the system further comprises at least onerelease mechanism configured to compromise the mechanical barrier,thereby releasing the second chemical such that the second chemicalreacts with the first chemical.

In some implementations, the at least one release mechanism comprises aheat producing device.

In some implementations, the at least one release mechanism comprises amechanical device configured to facilitate movement of at least one ofthe first chemical and the second chemical.

In some implementations, a pressure level of the produced fluid isbetween 15 psi and 40 psi.

In some implementations, a pressure source for providing a pressurizedfluid to facilitate conductive gel deployment in a wearable medicaldevice, the pressure source comprising: a reservoir containing apressurized fluid; and at least one release mechanism configured tocause a release of the pressurized fluid from the reservoir to an exitport of the pressure source when the wearable medical device ispreparing to deliver a therapeutic shock to a patient, is provided.

In some implementations, the at least one release mechanism comprises atleast one heating element.

In some implementations, the reservoir comprises a meltable plugpositioned in contact with the at least one heating element andconfigured to melt upon application of a current to the at least oneheating element, thereby resulting in release of the pressurized fluidthrough the exit port.

In some implementations, the meltable plug comprises at least one of ametal solder and an epoxy resin.

In some implementations, the pressure source further comprises: apiercing device positioned adjacent to a pierceable end of thereservoir; and a spring mechanism configured to facilitate movement ofat least one of the piercing device and the reservoir, thereby resultingin a piercing of the pierceable end of the reservoir and release of thepressurized fluid through the exit port.

In some implementations, the spring mechanism comprises a meltableretaining mechanism positioned adjacent to at least one heating element,wherein the meltable retaining mechanism is configured to melt uponapplication of a current to the at least one heating element, therebyresulting in the movement of at least one of the piercing device and thereservoir.

In some implementations, the piercing device comprises a drillpositioned such that a drill bit is adjacent to the pierceable end ofthe reservoir.

In some implementations, application of a current to the drill resultsin rotational movement of the drill bit such that the drill bitpenetrates the pierceable end of the reservoir.

In some implementations, the at least one release mechanism comprises apiston position to block flow of the pressurized fluid from thereservoir to the exit port, wherein the piston is configured to slidablyrelease the pressurized fluid to the exit port.

In some implementations, the pressure source further comprises: a springmechanism configured to slide the piston to facilitate release of thepressurized fluid.

In some implementations, the pressure source further comprises at leastone retaining element configured to oppose a spring force exerted by thespring mechanism to prevent movement of the piston, wherein the at leastone retaining element is positioned adjacent to at least one heatingelement and is configured to melt upon application of a current to theat least one heating element, thereby resulting in movement of thepiston and release of the pressurized fluid to the exit port.

In some implementations, the at least one release mechanism comprises amovable piercing device positioned adjacent to a pierceable end of thereservoir.

In some implementations, the moveable piercing device comprises a motorconfigured to move puncturing device through into the pierceable end ofthe reservoir, thereby resulting in release of the pressurized fluid.

In some implementations, the motor comprises at least one of a solenoidand an expanding wax actuator.

In some implementations, a pressure level of the pressurized fluid afterrelease is between 15 psi and 40 psi.

In some implementations, a system for providing therapy to a patient,the system comprising: a garment; a monitor configured to monitor atleast a physiological parameter of a patient; and a plurality of therapyelectrodes operably connected to the monitor and disposed in thegarment, each of the plurality of therapy electrodes comprising apressure source for providing a pressurized fluid to facilitateconductive gel deployment in a wearable medical device, the pressuresource comprising a reservoir containing a pressurized fluid, and atleast one release mechanism configured to cause a release of thepressurized fluid from the reservoir to an exit port of the pressuresource when the monitor is preparing to deliver a therapeutic shock to apatient, is provided.

In some implementations, each of the plurality of therapy electrodefurther comprise at least one conductive surface configured to deliverthe therapeutic shock.

In some implementations, the at least one release mechanism comprises:at least one heating element; and a meltable plug positioned in contactwith the at least one heating element and configured to melt uponapplication of a current to the at least one heating element, therebyresulting in release of the pressurized fluid through the exit port.

In some implementations, the pressure source further comprises: apiercing device positioned adjacent to a pierceable end of thereservoir; and a spring mechanism configured to facilitate movement ofat least one of the piercing device and the reservoir, thereby resultingin a piercing of the pierceable end of the reservoir and release of thepressurized fluid through the exit port.

In some implementations, the at least one release mechanism comprises apiston position to block flow of the pressurized fluid from thereservoir to the exit port, wherein the piston is configured to slidablyrelease the pressurized fluid to the exit port.

In some implementations, the at least one release mechanism comprises amovable piercing device positioned adjacent to a pierceable end of thereservoir.

In some implementations, a pressure level of the pressurized fluid afterrelease is between 15 psi and 40 psi.

In some implementations, a method for providing electrotherapy from anambulatory electrotherapy device comprising: providing an electrode;providing at least one reservoir comprising a conductive gel; providingat least one pressure source comprising a chemical reaction chambercomprising a first chemical and a second chemical isolated from eachother by a mechanical barrier, wherein the mechanical barrier isconfigured to be compromised upon receiving a signal from anelectrotherapy device controller, and wherein the first chemical andsecond chemical come into contact when the mechanical barrier iscompromised to produce a sufficient amount of fluid to generate asufficient pressure within the chamber, is provided.

In some implementations, the pressure source comprises producing carbondioxide by a reaction of the first chemical and the second chemical.

In some implementations, the first chemical is a metal carbonate orbicarbonate and the second chemical is an acid.

In some implementations, an amount of the metal carbonate or bicarbonateand the acid is sufficient to produce carbon dioxide in an amount tosupply the sufficient pressure of from about 15 psi to about 50 psi.

In some implementations, the pressure source comprises producing carbondioxide, nitrogen, oxygen, or mixtures thereof.

BRIEF DESCRIPTION OF THE DRAWINGS

Various aspects of at least one example are discussed below withreference to the accompanying figures, which are not intended to bedrawn to scale. The figures are included to provide an illustration anda further understanding of the various aspects and examples, and areincorporated in and constitute a part of this specification, but are notintended as a definition of the limits of any particular example. Thedrawings, together with the remainder of the specification, serve toexplain principles and operations of the described and claimed aspectsand examples. In the figures, each identical or nearly identicalcomponent that is illustrated in various figures is represented by alike numeral. For purposes of clarity, not every component may belabeled in every figure.

FIG. 1 depicts a wearable medical device, in accordance with an exampleof the present disclosure.

FIG. 2 depicts a plan view of a therapy electrode that can be used withthe wearable medical device of FIG. 1.

FIG. 3 depicts a pressure source that uses a chemical reaction toproduce a pressurized fluid, in accordance with an example of thepresent disclosure.

FIG. 4 depicts a pressure source that uses a chemical reaction toproduce a pressurized fluid, in accordance with an example of thepresent disclosure.

FIGS. 5A and 5B depict pressure sources that uses a meltable plug, inaccordance with an example of the present disclosure.

FIG. 6 depicts a pressure source that uses a puncturing pin, inaccordance with an example of the present disclosure.

FIGS. 7A and 7B depict multiple views of a pressure source that uses asliding valve, in accordance with an example of the present disclosure.

FIG. 8 depicts a pressure source that uses a puncturing pin, inaccordance with an example of the present disclosure.

FIG. 9 depicts a pressure source that uses a sliding valve, inaccordance with an example of the present disclosure.

FIG. 10 depicts a pressure source that uses a mechanical puncturingdevice, in accordance with an example of the present disclosure.

FIGS. 11A and 11B depict various views of a pressure source that uses apuncturing pin, in accordance with an example of the present disclosure.

FIG. 12 depicts an interface between a therapy electrode and a patient'sskin in accordance with an example of the present disclosure.

FIG. 13 depicts a schematic diagram illustrating various components ofan external medical device in accordance with an example of the presentdisclosure.

DETAILED DESCRIPTION

The particulars shown herein are by way of example and for purposes ofillustrative discussion of the various embodiments of the presentinvention only and are presented in the cause of providing what isbelieved to be the most useful and readily understood description of theprinciples and conceptual aspects of the invention. In this regard, noattempt is made to show details of the invention in more detail than isnecessary for a fundamental understanding of the invention, thedescription making apparent to those skilled in the art how the severalforms of the invention may be embodied in practice.

The present invention will now be described by reference to moredetailed embodiments. This invention may, however, be embodied indifferent forms and should not be construed as limited to theembodiments set forth herein. Rather, these embodiments are provided sothat this disclosure will be thorough and complete, and will fullyconvey the scope of the invention to those skilled in the art.

Unless otherwise defined, all technical and scientific terms used hereinhave the same meaning as commonly understood by one of ordinary skill inthe art to which this invention belongs. The terminology used in thedescription of the invention herein is for describing particularembodiments only and is not intended to be limiting of the invention. Asused in the description of the invention and the appended claims, thesingular forms “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise.

Unless otherwise indicated, all numbers expressing quantities ofingredients, reaction conditions, and so forth used in the specificationand claims are to be understood as being modified in all instances bythe term “about.” Accordingly, unless indicated to the contrary, thenumerical parameters set forth in the following specification andattached claims are approximations that may vary depending upon thedesired properties sought to be obtained by the present invention. Atthe very least, and not as an attempt to limit the application of thedoctrine of equivalents to the scope of the claims, each numericalparameter should be construed in light of the number of significantdigits and ordinary rounding approaches.

As used herein, the term “about” or “approximately” when referring to ameasurable value such as an amount, a pressure, and the like, is meantto encompass variations of +/−10%, more preferably +/−5%, even morepreferably, +/−1%, and still more preferably +/−0.1% from the specifiedvalue, as such variations are appropriate to perform the disclosedmethods.

Notwithstanding that the numerical ranges and parameters setting forththe broad scope of the invention are approximations, the numericalvalues set forth in the specific examples are reported as precisely aspossible. Any numerical value, however, inherently contains certainerrors necessarily resulting from the standard deviation found in theirrespective testing measurements. Every numerical range given throughoutthis specification will include every narrower numerical range thatfalls within such broader numerical range, as if such narrower numericalranges were all expressly written herein.

Additional advantages of the invention will be set forth in part in thedescription which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. It is to beunderstood that both the foregoing general description and the followingdetailed description are exemplary and explanatory only and are notrestrictive of the invention, as claimed.

This disclosure relates to improvements to a pressure source forfacilitating release and distribution of conductive gel for use with,for example, a wearable defibrillator. As will be defined in detailbelow, various designs can be used for a pressure source that includevarious alternatives for creating or causing the release of apressurized fluid. Upon creation or release of the pressurized fluid,the pressurized fluid facilitates deployment of, for example, conductivegel prior to delivery of a therapeutic shock to a patient.

During operation, and prior to administering a therapeutic shock, one ormore components of a wearable defibrillator can facilitate release of aconductive gel. For example, the wearable defibrillator can include agel deployment device configured to release a quantity of conductive gelbetween a therapy electrode and a patient's skin. The conductive gel canbe stored within one or more gel reservoirs in the gel deployment deviceuntil released. In order to release the conductive gel, the geldeployment device can include one or more pressure sources configured togenerate or release a pressurized fluid. The pressurized fluid can bedirected such that the pressurized fluid mechanically pushes theconductive gel out of the gel reservoirs. Various pressure sourceconfigurations and implementations are described herein in greaterdetail.

In one or more examples, the pressure sources as described herein can beconfigured to produce or release a pressurized fluid at a predeterminedpressure configured to cause release of the conductive gel from theconductive gel reservoirs. For example, a pressure source can beconfigured to create or release a pressurized fluid having a pressure ofapproximately 15 psi to 40 psi. In order to facilitate conductive gelrelease. In some implementations, the pressure sources can be configuredto produce or release a pressurized fluid at about 35 psi. In otherexamples, the pressure sources can be configured such that they releasea pressurized fluid that is configured to fill a certain cavity or spaceto a specific pressure. In certain implementations, the pressure sourcescan be configured to release a pressurized fluid such that a cavity orother open space is pressurized to a pressure of about 15 psi to 40 psi.In some configurations, the pressure sources can be configured torelease a pressurized fluid such that a cavity or other open space ispressurized to a pressure of about 35 psi. In some examples, thepressure sources can be configured to produce an applied force (e.g.,10.5 N/cm²/sec to 26.5 N/cm²/sec). Though the following descriptionrelated to levels of pressure produced by the pressure sources (e.g., inpounds per square inch), it should be appreciated that the functioningof the pressure sources as detailed herein can be described by way ofexerted force as well.

It should be noted that the above described pressure sources are merelyshown as introductory examples, and additional details are provided inthe following discussions of the figures.

As described below in additional detail, various configurations can beused for a pressure source. In some examples, the pressure source isconfigured to facilitate a chemical reaction therein. As a result of thechemical reaction, an amount of pressurized fluid such as carbon dioxidegas is produced and directed to, for example, a plurality of conductivegel reservoirs for facilitating release of the conductive gel storedtherein.

The pressurized fluid can include any non-noxious gas, such as carbondioxide, carbon monoxide, nitrogen, oxygen, nitric oxide, nitrogendioxide, nitrous oxide, hydrogen, fluorine, chlorine, helium, neon,argon, krypton, xenon, radon, or mixtures thereof. In someimplementations, the pressurized fluid includes carbon dioxide,nitrogen, oxygen, nitrogen dioxide, hydrogen, helium, neon, argon,krypton, xenon, radon, or mixtures thereof. In some implementations, thepressurized fluid includes carbon dioxide, nitrogen, oxygen, or mixturesthereof.

In another set of example pressure sources, a pressurized fluidreservoir is loaded with an amount of pressurized fluid such ascompressed nitrogen gas or compressed carbon dioxide gas. In certainimplementations, a mechanical release mechanism is configured to pierceor otherwise compromise the integrity of the pressurized fluidreservoir, thereby releasing the pressurized fluid. In some examples, amechanical release mechanism is configured to open a fluid conduit orotherwise establish a fluid connection between the pressurized fluidreservoir and an exit port.

Example Medical Devices

FIG. 1 illustrates an example medical device 100 that is external,ambulatory, and wearable by a patient 102, and configured to implementone or more configurations described herein. For example, the medicaldevice 100 can be a non-invasive medical device configured to be locatedsubstantially external to the patient. Such a medical device 100 can be,for example, an ambulatory medical device that is capable of anddesigned for moving with the patient as the patient goes about his orher daily routine. For example, the medical device 100 as describedherein can be bodily-attached to the patient such as the LifeVest®wearable cardioverter defibrillator available from ZOLL® MedicalCorporation. Such wearable defibrillators typically are worn nearlycontinuously or substantially continuously for two to three months at atime. During the period of time in which they are worn by the patient,the wearable defibrillator can be configured to continuously orsubstantially continuously monitor the vital signs of the patient and,upon determination that treatment is required, can be configured todeliver one or more therapeutic electrical pulses to the patient. Forexample, such therapeutic shocks can be pacing, defibrillation, ortranscutaneous electrical nerve stimulation (TENS) pulses.

The medical device 100 can include one or more of the following: agarment 110, one or more sensing electrodes 112 (e.g., ECG electrodes),one or more therapy electrodes 114, a medical device controller 120, aconnection pod 130, a patient interface pod 140, a belt 150, or anycombination of these. In some examples, at least some of the componentsof the wearable medical device 100 can be configured to be affixed tothe garment 110 (or in some examples, permanently integrated into thegarment 110), which can be worn about the patient's torso.

The controller 120 can be operatively coupled to the sensing electrodes112, which can be affixed to the garment 110, e.g., assembled into thegarment 110 or removably attached to the garment, e.g., using hook andloop fasteners. In some implementations, the sensing electrodes 112 canbe permanently integrated into the garment 110. The controller 120 canbe operatively coupled to the therapy electrodes 114. For example, thetherapy electrodes 114 can also be assembled into the garment 110, or,in some implementations, the therapy electrodes 114 can be permanentlyintegrated into the garment 110. Additionally, the therapy electrodes114 can include one or more conductive gel deployment devices, e.g., asshown in U.S. Patent Application Publication No. 2015/0005588 entitled“Therapeutic Device Including Acoustic Sensor,” the content of which isincorporate herein by reference. Additional examples of gel deploymentdevices can be found in, for example, U.S. patent application Ser. No.15/196,638 filed Jun. 29, 2016 and entitled “Conductive Gel Release andDistribution Devices,” the content of which is hereby incorporated byreference in its entirety.

Component configurations other than those shown in FIG. 1 are possible.For example, the sensing electrodes 112 can be configured to be attachedat various positions about the body of the patient 102. The sensingelectrodes 112 can be operatively coupled to the medical devicecontroller 120 through the connection pod 130. In some implementations,the sensing electrodes 112 can be adhesively attached to the patient102. In some implementations, the sensing electrodes 112 and therapyelectrodes 114 can be included on a single integrated patch andadhesively applied to the patient's body.

The sensing electrodes 112 can be configured to detect one or morecardiac signals. Examples of such signals include ECG signals, heartsounds, and/or other sensed cardiac physiological signals from thepatient. The sensing electrodes 112 can also be configured to detectother types of patient physiological parameters, such as tissue fluidlevels, lung sounds, respiration sounds, patient movement, etc. In someexamples, the therapy electrodes 114 can also be configured to includesensors configured to detect ECG signals as well as other physiologicalsignals of the patient. The connection pod 130 can, in some examples,include a signal processor configured to amplify, filter, and digitizethese cardiac signals prior to transmitting the cardiac signals to thecontroller 120. One or more therapy electrodes 114 can be configured todeliver one or more therapeutic defibrillating shocks to the body of thepatient 102 when the medical device 100 determines that such treatmentis warranted based on the signals detected by the sensing electrodes 112and processed by the controller 120.

FIG. 2 is a plan view of an electrode portion of a therapy electrodeassembly that includes a gel deployment device and which can be usedwith a wearable medical device, such as the wearable defibrillatordescribed above with respect to FIG. 1. The gel deployment device, whenactivated, can dispense an electrically conductive gel onto the exposedsurface of the electrode portion of the therapy electrode assembly that,in use, is placed most proximate to the subject's body.

As shown in FIG. 2, the electrode portion 200 can be a multiple layerlaminated structure that includes an electrically conductive layer(disposed on the bottom surface of the therapy electrode 200). In use,the electrically conductive layer can be disposed substantially adjacentto the subject's skin, although the conductive layer need not makedirect contact with the subject, as portions of the garment 110 (asshown in FIG. 1) and/or portions of the subject's clothing can bepresent between the electrically conductive layer and the subject'sskin. In some implementations, the garment 110 can include a pocket orother similar structure including a metallic mesh that can be configuredto act as an interface between the electrically conductive layer and thepatient's skin. In an example, the metallic mesh can include a knottedfabric having a silver coating. Upon deployment of the conductive gel,an electrical pathway can be defined between the electrically conductivelayer and the patient's skin.

As shown in FIG. 2, various components of the gel deployment device canbe disposed on a side of the therapy electrode 200 (e.g., the top-sideshown in FIG. 2) that is opposite the side on which the conductive layeris formed.

The therapy electrode 200 can include a plurality of conductive gelreservoirs 210, each of which has a respective gel delivery outlet 220.Each of the gel reservoirs can be fluidly coupled to a fluid channel 230and a pressure source 240. The pressure source 240 can be fluidlycoupled to the fluid channel 230 and, when activated by an activationsignal, can release a pressurized fluid, such as compressed gas, intothe channel 230. The hydraulic pressure of the fluid from the activatedpressure source 240 in the fluid channel 230 can force the conductivegel stored in each of the plurality of gel reservoirs out of theplurality of gel delivery outlets 220 through apertures formed in theelectrically conductive layer and onto the exposed surface of theelectrically conductive layer that, in use, is placed most proximate tothe subject's body. The apertures in the electrically conductive layercan be substantially aligned with the plurality of gel delivery outlets220 so that when activated, the electrically conductive gel can bedispensed onto the exposed surface of the electrode portion that isdisposed most proximate to the subject's body.

Overview of Pressure Sources Using Chemical Reactions

As noted above, a pressure source can be configured to facilitate achemical reaction. As a result of the chemical reaction, an amount ofpressurized fluid can be produced and directed to, for example, aplurality of conductive gel reservoirs for facilitating release of theconductive gel stored therein.

The pressurized fluid can include any non-noxious gas. Examples arediscussed above.

FIGS. 3 and 4 illustrate various example configurations for a pressuresource that incorporates a chemical reaction to produce a pressurizedfluid. The pressure sources can include a case design that allows forthe storage and timely mixing of two or more chemicals to produce thepressurized fluid. For example, the chemical reaction can include mixingtwo chemicals together to produce a chemical reaction, resulting in thecreation of a pressurized fluid. The chemical reaction can include, forexample, mixing two or more fluids together, mixing one or more fluidswith one or more solids, or mixing two or more solids together.

In certain implementations, the chemical reaction can include mixing anacid with a base to produce a pressurized fluid. The resulting carbondioxide gas can be directed by the pressure source through an exit portof the pressure source and into, for example, fluid channel 230 asdescribed above. The carbon dioxide gas can apply hydraulic pressure tothe individual gel reservoirs 210, thereby facilitating release ofconductive gel stored within the conductive gel reservoirs.

Depending upon the intended application of the pressure source, acertain pressure level of the pressurized fluid can be configured to,for example, facilitate conductive gel release in a conductive geldeployment device. For example, the pressure level of the pressurizedfluid can be configured based upon the internal volume of the fluidchannel (as well as any additional spaces the pressurized fluid isconfigured to fill, such as air gaps or spaces in the gel reservoirs).The pressure level can also be configured based upon an applied pressurelevel for releasing the conductive gel from the gel reservoirs. Incertain implementations, the gel reservoirs can include a frangible sealconfigured to release the conductive gel at an applied pressure of about15 psi. This applied pressure, in combination with the internal volumethe pressurized fluid is configured to fill, can be used to determine atotal overall pressure level for the pressurized fluid. For example, thecombined internal volume the pressurized fluid is configured to fill canbe approximately 25 cubic centimeters. In other examples, the internalvolume the pressurized fluid is configured to fill can be approximately5-50 cm³. In other examples, the internal volume can change as theconductive gel is released (i.e., to account for the space in the gelreservoirs previously occupied by the conductive gel). As such, incertain implementations, the initial internal volume can be approximate5-10 cm³ and the final internal volume can be approximately 10-50 cm³.

In some implementations, the pressure sources including chemicalreactions as described below can be configured to produce or release apressurized fluid at approximately 5 to 100 psi. In someimplementations, the pressure sources including chemical reactions asdescribed below can be configured to produce or release a pressurizedfluid at approximately 15 psi to 40 psi. In some examples, the pressuresources including chemical reactions can be configured to produce orrelease a pressurized fluid at about 35 psi, or at a similar pressure tofill the internal volume (such as a one or more fluid conduits used in agel deployment device as described above) to a pressure of about 35 psi.

It should be noted that the combination of an acid and a base asdescribed above to produce a pressurized gas is presented by way ofexample only.

In certain implementations, the chemical reaction can include applyingan acidic solution to a reactive metal.

Additionally, while the following discussions are generally directed tochemical reactions, physical reactions can be included as well. Forexample, a nucleation process can be used to produce an amount ofpressurized fluid.

In some implementations, a liquid including a suspended gas (such as acarbonated liquid including suspended carbon dioxide) can be mixed witha solid including a surface covered with microscopic features such aspeaks and valleys. When the solid is introduce to the liquid, thesuspended gas attaches to the microscopic features, forming bubblesaround all the features. Once the amount of forming bubbles exceeds theamount of gas the liquid can stably suspend, excess gas can be releasedfrom the liquid as a pressurized fluid. As above, this pressurized fluidcan be directed to the gel reservoirs for facilitation of the conductivegel release.

Specific examples of pressure sources including chemical reactions aredescribed below in additional detail.

Chemical Reaction Example Using a Heat Source

FIG. 3 illustrates a pressure source 300 configured to produce apressurized fluid as, for example, a byproduct of a chemical reaction.In operation, the pressure source 300 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above, e.g.,replacing pressure source 240 as discussed in reference to therapyelectrode 200. A controller, such as medical device controller 120, canbe operably connected to the pressure source 300. The medical devicecontroller 120 can be configured to provide an electrical signal to thepressure source 300 prior to delivery of, for example, a therapeuticshock to a patient. The electrical signal can be configured tofacilitate or otherwise initiate a chemical reaction configured toproduce a pressurized fluid. The pressurized fluid can then be directedthrough the fluid channel 230 to the conductive gel reservoirs 210,thereby causing release of the conductive gel stored therein.

The pressurized fluid can include any non-noxious gas. Examples arediscussed above.

The pressure source 300 can include a case 302 configured to contain thechemicals and other components related to facilitating a chemicalreaction. Depending upon the design of the pressure source 300, and thetypes of chemicals contained therein, various materials and methods ofmanufacture can be used to construct the case 302. For example, thechemical reaction used by the pressure source 300 can be configured toproduce approximately 35 psi. As such, the material used for themanufacture of case 302 can be selected and configured to withstand anapplied pressure greater than 35 psi plus some safety margin (e.g., anadditional about 1-50 psi). The case 302 can be made of plastic, metal,metal alloy, ceramic, and/or a combination thereof. In certainimplementations, the case 302 can be molded from a thermoplastic polymerand/or a thermoset polymer. In some examples, the case 302 can be shapedsuch that any pressurized fluids contained therein are directed in aparticular direction. For example, the case 302 can be shaped like acone having an opening or exit port at the point or narrow end, atapering cylinder having an opening or exit port at the narrow end, apyramid having an opening or exit port at one of the points, and othersimilar shapes that provide one or more geometric features for directedpressurized fluid flow.

In some implementations, the case 302 is made of a clear or transparentmaterial to allow visual monitoring of the contents of the case.

The case 302 can be made of a thermoplastic material. For example, thethermoplastic material can be high density polyethylene, low densitypolyethylene, ultra high-molecular weight polyethylene, polypropylene,nylon and polyethylene terephthalate. Alternatively, it is understoodthat any viable thermoplastic material may be used. The material may betransparent, opaque or partially opaque.

Examples of thermoplastic polymers include polystyrene, polyetherketone,polyetheretherketone, polyetherketoneketone, polyethersulfone,polycarbonate, polyolefin such as polypropylene, polyethylene, or cyclicolefin, polyester such as polyethylene terephthalate or polyethylenenapthalate, polyamide (nylon), or other well-known materials in theplastics art. Amorphous plastics such as amorphous nylon exhibit hightransparency and may also be suitable.

Thermoset resins include epoxy, epoxy novolac, phenolic, polyurethane,and polyimide.

In some implementations, the case 302 can be manufactured from acopolymer such as an ethylene acid copolymer through an injectionmolding or thermoforming process. For example, the case 302 can bemanufactured from an ionomer resin of ethylene acid copolymer (“theionomer resin”) having a density of approximately 0.94 g/cm³. As such,the tensile strength of the ionomer resin can be configured based uponthe thickness of the ionomer resin. An example of a commerciallyavailable ionomer resin of ethylene acid copolymer is Surlyn®, which isavailable from DuPont™.

The thickness of the walls of the case 302 can be configured such thatthe case 302 is configured to withstand an applied pressure of greaterthan, for example, about 100 psi. In certain implementations, theionomer resin has a thickness of approximately 0.125 inches canwithstand an applied pressure of approximately 250 psi.

In certain implementations, a clear plastic such as polycarbonate or acomposite plastic blend (e.g., an ethylene acid copolymer andpolycarbonate blend) can be used to manufacture case 302 if, forexample, the case 302 is to be subjected to visual inspection (e.g., toconfirm that the chemical reaction has not occurred prior toinstallation of the pressure source). Depending upon the tensilestrength of the blended materials, a thickness for the walls of the case302 can be configured such that the case is configured to withstand theapplied pressure as described above.

Additionally, case 302 can be manufactured from a material having arelatively low water vapor transmission rate. The ionomer resin has awater vapor transmission rate of about 0.8 g/100 in²/day. Using amaterial with a low permeability such as the ionomer resin can providean advantage of a longer shelf-life of a chemical reaction-basedpressure source relative to conventional configurations as the rate ofevaporation of any liquid chemicals through the ionomer resin is low.

In certain implementations, the case 302 can be manufactured from aplastic material using an injection molding process. In certainimplementations, the case 302 can be manufactured from the ionomer resinin a design (e.g., having a specific geometry and wall thickness)capable of both housing enough chemicals as needed for the chemicalreaction while still maintaining its structural integrity after thechemical reaction (e.g., the case 302 is configured to handle thepressure of the fluid produced as a result of the chemical reaction). Inadditional implementations, the case 302 can be formed by athermoforming process, or other similar forming process.

The case 302 can also be made from a non-reactive metal such asstainless steel. The stainless steel can be stamped, rolled, orsimilarly formed to contain the chemicals and other components relatedto facilitating the chemical reaction.

In certain implementations, the case 302 can be configured and formedsuch that it defines at least one exit port 304 for directing apressurized fluid (produced by, for example, a chemical reaction withinthe case 302). Depending upon the design of the pressure source 300, theexit port 304 can include a valve (e.g., a one-way flow valve) toprevent contamination or foreign chemicals from entering into the case302. In certain implementations, the valve can be configured to open ata predetermined pressure (e.g., about 5 psi to 20 psi) to preventchemicals from escaping the case 302 prior to the chemical reaction. Insome examples, the valve can be configured to open at about 10 psi.

The pressure source 300 can include a first chemical 306 and a secondchemical 308. The first chemical 306 can be a solid base loaded into thecase 302 in, for example, a powder or compressed solid form. The secondchemical 308 can be contained in an isolating container 310. Theisolating container 310 can be configured to act as a mechanical barrierpositioned to provide isolation of the second chemical 308 from thefirst chemical 306 until the second chemical 308 is released orotherwise mixed with first chemical 306, thereby eliminating unwantedand/or untimely reactions.

The second chemical 308 can be a liquid chemical such as an acid. Theisolating container 310 can be filled with the second chemical prior toinsertion into the case 302. In certain implementations, to facilitateejection of the second chemical 308 from the isolating container 310,the second chemical 308 can be filled into the isolating container 310at, for example, 15 psi to 35 psi.

In some examples, the second chemical 308 can be filled into theisolating container 310 at about 25 psi. Thus, when the isolatingcontainer 310 is compromised, the second chemical 308 is forciblyreleased from the isolating container 310. In certain implementations,an external pressure applying device such as a leaf spring or an elasticband can apply an external pressure to the isolating container 310. Forexample, as shown in FIG. 3, a set of leaf springs 314 can be positionedadjacent to the isolating container 310 and be configured to apply anexternal pushing force against the isolating container 310. When theisolating container 310 is compromised, the leaf springs 314 can assistin the release of the second chemical 308 from the isolating container310.

In some implementations, the first chemical 306 is a metal carbonate orbicarbonate and the second chemical 308 is an acid. When the metalcarbonate or bicarbonate and the acid mix together, a reaction occurs toproduce carbon dioxide, salt, and water.

The metal carbonate can be any metal carbonate. In some implementations,the metal carbonate is lithium carbonate, sodium carbonate, potassiumcarbonate, rubidium carbonate, cesium carbonate, beryllium carbonate,magnesium carbonate, calcium carbonate, strontium carbonate, bariumcarbonate, manganese carbonate, iron carbonate (siderite), cobaltcarbonate, nickel carbonate, copper carbonate, zinc carbonate, silvercarbonate, cadmium carbonate (otavite), aluminum carbonate, thalliumcarbonate, lead carbonate, ammonium carbonate, bismuth subcarbonate,lanthanum carbonate, uranyl carbonate, or mixtures thereof. In someimplementations, the metal carbonate is sodium carbonate, potassiumcarbonate, magnesium carbonate, calcium carbonate, copper carbonate,zinc carbonate, ammonium carbonate, or mixtures thereof.

The metal bicarbonate can be any metal bicarbonate. In someimplementations, the metal bicarbonate is lithium bicarbonate, sodiumbicarbonate, potassium bicarbonate, cesium bicarbonate, magnesiumbicarbonate, calcium bicarbonate, ammonium bicarbonate, or mixturesthereof. In some implementations, the metal bicarbonate is sodiumbicarbonate, potassium bicarbonate, magnesium bicarbonate, calciumbicarbonate, ammonium bicarbonate, or mixtures thereof.

The acid can be any acid in a concentration such that it can react toproduce carbon dioxide but can be safely stored in the case 302. Theacid can be a mineral acid, sulfonic acid, carboxylic acid, halogenatedcarboxylic acid, or mixtures thereof. In some implementations, the acidis hydrofluoric acid, hydrochloric acid, hydrobromic acid, hydroiodicacid, hypochlorous acid, chlorous acid, chloric acid, perchloric acid,hypobromous acid, bromous acid, bromic acid, perbromic acid, hypoiodousacid, iodous acid, iodic acid, periodic acid, sulfuric acid, nitricacid, phosphoric acid, fluorosulfuric acid, fluoroantimonic acid,fluoroboric acid, hexafluorophosphoric acid, chromic acid,methanesulfonic acid, ethanesulfonic acid, benzensulfonic acid,p-toluenesulfonic acid, trifluoromethanesulfonic acid, polystyrenesulfonic acid, acetic acid, citric acid, formic acid, gluconic acid,lactic acid, oxalic acid, tartaric acid fluoroacetic acid,tirfluoroacetic acid, chloroacetic acid, dichloroacetic acid,trichloroacetic acid, ascorbic acid, or mixtures thereof. In someimplementations, the acid is hydrochloric acid, sulfuric acid, nitricacid, phosphoric acid, acetic acid, or mixtures thereof.

The concentration of the acid can be adjusted by adding a solvent suchas water. In some implementations, the concentration of the acid isadjusted such that the pH of the acid is in the range of about 2 to lessthan 7. In some implementations, acids with a pH of less than 2 can beused in small quantities—e.g., less than 0.1 gm in case having a volumeof about 25 cm³.

In some implementations, the pressure source 300 can include a firstchemical 306 and a second chemical 308, wherein the first chemical 306and the second chemical 308 are selected to produce nitrogen gas oroxygen gas.

To produce oxygen gas, the first chemical 306 can be sodium chlorate,potassium perchlorate, potassium permanganate, potassium iodide, ormixtures thereof and the second chemical 308 can be hydrogen peroxide,barium peroxide, iron powder, or mixtures thereof. Yeast can be used asthe first chemical 306 in some implementations. In some implementations,the second chemical 308 is hydrogen peroxide. In some implementations,the second chemical 308 is hydrogen peroxide and the first chemical 306can be one or a mixture of potassium iodide, yeast, and potassiumpermanganate.

To produce nitrogen gas, the first chemical 306 can be an ammoniumcompound and the second chemical 308 can be a chemical that reacts withthe ammonium compound to produce nitrogen gas. Examples of the ammoniumcompound include ammonium nitrite, ammonium nitrate, ammonium, chloride,ammonium dichromate, ammonium hydroxide, or mixtures thereof. Examplesthe second chemical 408 can be sodium nitrite, potassium nitrite,calcium nitrite, or other nitrite compound.

Nitrogen gas can also be produced by the reaction of hypochlorites orhypobromites on ammonia, reduction of nitric and/or nitrous oxides,reaction of ammonia gas with a nitrite compound, or combinations ofthese reactions.

It should be noted that the quantities provided of the first chemical306 and the second chemical 308 can be varied depending upon the sizeand shape of the case 302 and the amount of pressure the chemicalreaction is configured to produce. For example, to produce a higherpressure than, for example, the implementations as described above,additional quantities of the first chemical 306 and the second chemical308 can be used in a similarly shaped case 302. In some implementations,more reactive chemicals can be used to produce a pressurized fluidhaving a higher pressure level.

The first chemical 306 can be added in an amount of about 0.001 grams toabout 1000 grams. In some embodiments the first chemical 306 can beadded in an amount of 0.001 to about 50 wt % of the total amount of thefirst chemical 306 and the second chemical 308. The second chemical 308can be added in an amount of about 0.001 grams to about 1000 grams. Insome embodiments the second chemical 308 can be added in an amount of0.001 to about 50 wt % of the total amount of the first chemical 306 andthe second chemical 308.

In some embodiments, the first chemical 306 and the second chemical 308are present in an amount sufficient to produce an amount of carbondioxide, which produces a pressure of from about 5 psi to about 100 psi.In some implementation, the pressure is from about 10 psi to about 70psi. In some implementations, the pressure is from about 15 psi to about50 psi. In some implementations, the pressure is from about 15 psi toabout 35 psi.

In certain implementations, the isolating container 310 can be made froma membrane or another material that, in response to an applied heat orforce, can be structurally compromised to release the second chemical308 such that it mixes with the first chemical 306. In certainimplementations, the isolating container 310 can be configured such thatit is structurally compromised upon application of heat from one or moreheat sources. For example, as shown in FIG. 3, a heating element such asresistive wire 312 can be placed adjacent to the isolating container310, e.g., wrapped around the isolating container 310 or otherwisepressed against a portion of the isolating container 310. The isolatingcontainer 310 can be formed from a meltable membrane such as athermoplastic configured to melt at a predetermined melting point. Incertain implementations, the isolating container 310 can be manufacturedfrom polyethylene having a melting point of approximately 239-275° F. Insome examples, the isolating container 310 can be manufactured from amaterial having a low evaporation permeability (e.g., a material havinga low water vapor transmission rating) when compared to conventionalthermoplastics. A material with a low evaporation permeability canprovide the advantage of an extended shelf life of the pressure source300 as the second chemical 308 is less likely to evaporate or leak fromthe isolating container 310.

The resistive wire 312 can be constructed from a material that producesheat in response to an applied current. For example, the resistive wire312 can be made from nickel chromium wire. The thickness of theresistive wire 312 can be selected such that the temperature of thewire, when an appropriate current is applied, exceeds the melting pointof the isolating container 310. For example, a 20-gauge to a 28-gaugewire can be used, the wire configured to heat to approximately 350° F.to 450° F. In certain implementations, a 24-gauge nickel chromium wirehaving a 0.020-inch diameter can heat to 400° F. at relatively lowamperages as compared to a similarly sized copper wire.

In order to facilitate mixing of the first chemical 306 and the secondchemical 308, a current can be applied to the resistive wire 312. Theresistive wire 312 can heat up past the melting point of the isolatingcontainer 310, thereby causing a puncturing or rupturing of theisolating container 310 and release of the second chemical 308 (e.g.,through the internal pressure of the second chemical 308 within theisolating container 310 as described above). The second chemical 308 canmix with the first chemical 306, thereby producing a pressurized fluid.The shape of the case 302 can direct the pressurized fluid out of theexit port 304. The exit port 304 can be connected to a fluid channel in,for example, the therapy electrode 200 as described above in regard toFIG. 2. The pressurized fluid can be directed through the fluid channelto one or more gel reservoirs, thereby facilitating release ofconductive gel stored in the gel reservoirs.

In certain implementations, alternate release methods can be used topuncture or otherwise compromise the isolating container 310 and releasethe second chemical 308. For example, a puncturing pin and actuationdevice (such as a small solenoid) can be used to puncture the isolatingcontainer 310. In certain implementations, the isolating container 310can be configured as a syringe configured to eject a quantity of thesecond chemical 308 in response to, for example, a force pressingagainst a plunger of the syringe. In some examples, an alternativemelting device can be used in place of the resistive wire 312. Forexample, a small laser can be configured to focus an emitted laser beamor pulse onto the isolating container 310 to melt a small portion of theisolating container 310.

Depending upon the resistance of the resistive wire 312, and desiredtiming for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to heat the resistive wire 312)at the appropriate time (e.g., providing for adequate timing for thechemical reaction to occur and for the subsequent release of theconductive gel). In some examples, the pressure source 300 can alsoinclude a localized power source that, in response to the signal fromthe medical device controller 120, is configured to provide a current tothe resistive wire 312, thereby heating the resistive wire.

As noted above, in operation, the pressure source 300 can be integratedinto a therapy electrode such as therapy electrode 200 as discussedabove, e.g., replacing pressure source 240 as discussed in reference totherapy electrode 200. A controller, such as medical device controller120, can be operably connected to the pressure source 300. The medicaldevice controller 120 can be configured to provide an electrical signalto the pressure source 300 prior to delivery of, for example, atherapeutic shock to a patient. The electrical signal can include acurrent to be directed to the resistive wire 312, thereby heating theresistive wire 312. Once heated, the resistive wire 312 can melt theisolating container 310, resulting in the release of the second chemical308 from the isolating container 310. The second chemical 308 can mixwith the first chemical 306, causing a chemical reaction. The chemicalreaction can produce a pressurized fluid (e.g., pressurized carbondioxide gas), which is directed through the exit port 304. Thepressurized fluid can flow through the fluid channel 230 to each of theconductive gel reservoirs 210. The pressurized fluid can cause releaseof the conductive gel contained within the conductive gel reservoirs210, thereby resulting in the conductive gel flowing through theapertures in the electrically conductive layer that is substantiallyproximate the patient's body. The medical device controller 120 can thenfacilitate delivery of the therapeutic shock.

It should be noted that the arrangement of components as shown in FIG. 3is by way of example only. For example, the isolating container 310 isshown as positioned in the center of the case 302 for explanatorypurposes only. In certain implementations, the isolating container 310can be positioned against a wall of the case 302, at one end of the case302, or at any location within the case 302 that still provides foradequate chemical mixing prior to the chemical reaction. Additionally,the pressure source 300 is shown as having the second chemical 308positioned inside the isolating container 310. In other designs, thefirst chemical 306 can be placed within the isolating container 310 andthe second chemical 308 can be arranged solely inside case 302.

Chemical Reaction Example Using a Movable Piston

FIG. 4 illustrates a pressure source 400 configured to produce apressurized fluid as a result of a chemical reaction. In operation, thepressure source 400 can be integrated into a therapy electrode such astherapy electrode 200 as discussed above, e.g., replacing pressuresource 240 as discussed in reference to therapy electrode 200. Acontroller, such as medical device controller 120, can be operablyconnected to the pressure source 400. The medical device controller 120can be configured to provide an electrical signal to the pressure source400 prior to delivery of, for example, a therapeutic shock to a patient.The electrical signal can be configured to facilitate or otherwiseinitiate a chemical reaction configured to produce a pressurized fluid.The pressurized fluid can then be directed through the fluid channel 230to the conductive gel reservoirs 210, thereby causing release of theconductive gel stored therein.

The pressurized fluid can include any non-noxious gas. Examples arediscussed above.

The pressure source 400 can include a case 402 configured to contain thechemicals and other components related to facilitating a chemicalreaction. The case 402 can be formed such that it can define at leastone exit port 404 for directing a pressurized fluid (produced by, forexample, a chemical reaction within the case 402). Depending upon thedesign of the pressure source 400, the exit port 404 can include a valve(e.g., a one-way flow valve) to prevent contamination or foreignchemicals from entering into the case 402. Similarly, the valve can beconfigured to open at a predetermined pressure (e.g., 10 psi) to preventchemicals from escaping the case 402 prior to the chemical reaction.

As described above in regard to case 302, case 402 can be made from thesame material(s) and has the same characteristics as discussed abovewith regard to case 302.

The pressure source 400 can include a first chemical 406 and a secondchemical 408. The first chemical 406 can be a metal carbonate orbicarbonate. In some implementations, the first chemical 406 can be asolid such as sodium bicarbonate loaded into the case 402 in, forexample a powder or compressed solid form.

The second chemical 408 remains separated from the first chemical 406by, for example, a piston 410. In some implementations, the secondchemical 408 is an acid.

The metal carbonate can be any metal carbonate, as discussed above.

The metal bicarbonate can be any metal bicarbonate as discussed above.

The acid can be any acid as discussed above.

In certain implementations, the piston 410 can be constructed from aplastic such as polyethylene, or a metal such as stainless steel oraluminum. The piston 410 can also include one or more O-rings 411positioned to prevent leakage of the second chemical 408 as well as toact as a mechanical barrier configured to create a seal between thefirst chemical and the second chemical. In some implementations, theO-rings 411 can be made from a thermoplastic elastomer such as syntheticrubber. The O-rings 411 can also be sized to produce a friction fitbetween the piston 410 and the case 402.

To facilitate movement of the piston 410, and thus mixing of the firstchemical 406 and the second chemical 408, the piston 410 can beconnected to a movement causing device such as a solenoid 412. Thesolenoid 412 can be configured to exert a pushing force on the piston410, thereby moving the piston 410 toward the first chemical 406 (asshown in FIG. 4), causing the release of the second chemical 408 intothe first chemical 406. The second chemical 408 can mix with the firstchemical 406, thereby producing a pressurized fluid. In certainimplementations, the shape of the case 402 can be configured and designto direct the pressurized fluid out of the exit port 404. The exit port404 can be connected to a fluid channel in, for example, the therapyelectrode 200 as described above in regard to FIG. 2. The pressurizedfluid can be directed through the fluid channel to one or more gelreservoirs, thereby facilitating release of conductive gel stored in thegel reservoirs.

Depending upon the electrical requirements of the solenoid 412, anddesired timing for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to move the solenoid 412) at theappropriate time (e.g., providing for adequate timing for the chemicalreaction to occur and for the subsequent release of the conductive gel).In some implementations, the pressure source 400 can also include alocalized power source that, in response to the signal from the medicaldevice controller 120, is configured to provide a current to thesolenoid 412, thereby facilitating movement of the solenoid 412.

As noted above, the pressure source 400 can be integrated into a therapyelectrode such as therapy electrode 200. For example, the pressuresource 400 can replace pressure source 240 as discussed in reference totherapy electrode 200. A controller, such as medical device controller120, can be operably connected to the pressure source 400. The medicaldevice controller 120 can be configured to provide an electrical signalto the pressure source 400 prior to delivery of, for example, atherapeutic shock to a patient. The electrical signal can be directed tothe solenoid 412. The solenoid 412 can move the piston 410 toward, forexample, exit port 404. Such movement of the piston 410 can result inthe second chemical 408 being released into the first chemical 406.

The second chemical 408 can mix with the first chemical 406, causing achemical reaction. The chemical reaction can produce a pressurized fluid(e.g., pressurized carbon dioxide gas) which can be directed through theexit port 404. The pressurized fluid can flow through the fluid channel230 to each of the conductive gel reservoirs 210. The pressurized fluidcan facilitate release of the conductive gel contained within theconductive gel reservoirs 210, resulting in the conductive gel flowingthrough the apertures in the electrically conductive layer that isproximate the patient's body. The medical device controller 120 can thendeliver the therapeutic shock.

It should be noted that pressure sources 300 and 400 are described aboveby way of example only. Similarly, the chemicals described in relationto the pressure sources 300 and 400, as well as the resulting chemicalreactions and pressurized fluids produced by those reactions aredescribed by way of example only.

In some implementations, the pressure source 400 can include a firstchemical 406 and a second chemical 408, wherein the first chemical 406and the second chemical 408 are selected to produce nitrogen gas oroxygen gas.

To produce oxygen gas, the first chemical 406 can be sodium chlorate,potassium perchlorate, potassium permanganate, potassium iodide, ormixtures thereof and the second chemical 408 can be hydrogen peroxide,barium peroxide, iron powder, or mixtures thereof. Yeast can be used asthe first chemical 406 in some implementations. In some implementations,the second chemical 408 is hydrogen peroxide. In some implementations,the second chemical 408 is hydrogen peroxide and the first chemical 406can be one or a mixture of potassium iodide, yeast, and potassiumpermanganate.

To produce nitrogen gas, the first chemical 406 can be an ammoniumcompound and the second chemical 408 can be a chemical that reacts withthe ammonium compound to produce nitrogen gas. Examples of the ammoniumcompound include ammonium nitrite, ammonium nitrate, ammonium, chloride,ammonium dichromate, ammonium hydroxide, or mixtures thereof. Examplesthe second chemical 408 can be sodium nitrite, potassium nitrite,calcium nitrite, or other nitrite compound.

Nitrogen gas can also be produced by the reaction of hypochlorites orhypobromites on ammonia, reduction of nitric and/or nitrous oxides,reaction of ammonia gas with a nitrite compound, or combinations ofthese reactions.

Chemical Reaction Examples

As described above, a pressure source (e.g., one of pressure sources 300and 400) can include two chemicals configured to mix such that aresulting reaction produces an amount of pressurized fluid containing agas such as carbon dioxide.

The pressurized fluid can include any non-noxious gas. Examples arediscussed above.

In some implementations, the pressurized fluid is produced from mixing afirst chemical and a second chemical to produce carbon dioxide, wherethe first chemical is a metal carbonate or bicarbonate and the secondchemical is an acid. The reaction of the metal carbonate or bicarbonatewith the acid produces safe byproducts including salt, water, and carbondioxide as shown below in reaction (1).

Metal Carbonate or Bicarbonate+Acid→Salt+Water+Carbon Dioxide  (1)

For example, the chemical reaction can include mixing an acid such ascitric or acetic acid with a basic solid such as sodium bicarbonate toproduce carbon dioxide gas with water, and sodium acetate. A specificchemical reaction example of reaction (1) is shown below in reaction(2).

NaHCO₃+CH₃COOH→CO₂+H₂O+CH₃COONa  (2)

The base can be added in an amount of about 0.001 grams to about 1000grams. In some embodiments the base can be added in an amount of 0.001to about 50 wt % of the total amount of the base and the acid. The acidcan be added in an amount of about 0.001 grams to about 1000 grams. Insome embodiments the acid can be added in an amount of 0.001 to about 50wt % of the total amount of the base and the acid.

In certain implementations, the first chemical or the second chemicalcan be a limiting agent. For example, a specific quantity of the firstchemical can be determine that, upon reaction, will produce anappropriate amount of pressurized gas. An amount of the second chemicalcan be determine that would fully react with the specific quantity ofthe first chemical. In certain embodiments, an additional buffer amountof the second chemical can be included. For example, an additional 5-25%of the second chemical can be included. In such an example, the firstchemical would act as a limiting agent as the first chemical would fullyreact with the second chemical (with an amount of excess second chemicalremaining, i.e., the additional buffer).

In some embodiments, the base and the acid are present in an amountsufficient to produce an amount of carbon dioxide, which produces apressure of from about 5 psi to about 100 psi. In some implementations,the pressure is from about 10 psi to about 70 psi. In someimplementations, the pressure is from about 15 psi to about 50 psi. Insome implementations, the pressure is from about 15 psi to about 35 psi.

As noted above, a specific amount of pressurized fluid can be createdduring the chemical reaction, the pressurized fluid being directed toindividual gel reservoirs to facilitate release of conductive gel storedtherein. For example, the pressurized fluid can be configured to fill aninternal volume of 25 cm³ to a pressure of approximately 50 psi (e.g., a35 psi pressure to facilitate release of the conductive gel from the gelreservoirs plus a 15 psi safety buffer to account for any unreactedchemicals or other potential complications during the chemicalreaction). In the above example chemical reaction, the resultingpressurized fluid is carbon dioxide, which has a molar mass of 44.0095g/mol at room temperature (e.g., approximately 295K). As such, basedupon the desired pressure (50 psi at standard atmospheric pressure), theinternal volume (25 cm³), and the molar mass of the carbon dioxide, anamount of carbon dioxide to be produced during the chemical reaction canbe calculated using the ideal gas law:

pV=nRT  (3)

where p is the pressure, V is the volume, n is the number of moles ofthe gas (represented as mass/mass of 1 mole), R is the ideal gasconstant (8.31446 J K⁻¹ mol⁻¹), and T is the temperature at the time ofreaction (e.g., approximately 295K or room temperature). As noted above,the pressure includes a safety buffer. This buffer can also be used toaccount for any changes in temperature during the reaction.

Substituting the values as noted above into the ideal gas law, theresulting equation is:

(50 psi at 1 atm)(25 cm³)=(mass of CO₂/44.0095 g/mol)(8.31441 J K⁻¹mol⁻¹)(295K).

Converting both pressure and volume to appropriate units (Pascal andcubic meters respectively) results in:

(344737.86 pa)(0.000025 m³)=(mass of CO₂/44.0095 g/mol)(8.31446 J K¹mol⁻¹)(295K).

Solving the above equation gives a mass of 0.15 g of CO₂ to be produced.Such a mass of CO₂ will result in the desired 50 psi in the internalvolume of 25 cm³. CO₂ has a density of about 1.98 g/L in its gaseousstate. As such, the above equation results in 0.075 liters of CO₂. Thus,a chemical reaction that produces 0.075 liters of CO₂ will result in a50 psi pressure in the internal volume of 25 cm³.

See Table 1 for calculations showing the amounts of sodium bicarbonateand acetic acid needed to produce a range of pressures (i.e., 1-100 psi)from the resulting carbon dioxide gas in a volume of 25 cm³.

The inventors have used commercially available acetic acid to producecarbon dioxide.

When the controller, e.g., medical device controller 120, triggers arelease of the conductive gel, the wire 312 can be heated, therebycausing a structural compromise of the isolating container 310 (e.g.,the wire 312 melts a hole in isolating container 310). The acetic acidcan then be released from the isolating container 310. In certainimplementations, leaf springs 314 can provide an external force againstthe isolating container 310, causing quicker release of the acetic acid.The acetic acid can then mix with the sodium bicarbonate in the case302, causing creation of the carbon dioxide gas. The carbon dioxide gascan be directed out of the case 302 via the exit port 304. The carbondioxide gas can then be directed by one or more fluid conduits, such asfluid channel 230, to the gel reservoirs.

In certain implementations, the speed of the reaction can be a criticalconsideration. For example, in a wearable defibrillator, when atreatment shock is imminent, it may be desirable to have the conductivegel deploy as quick as possible. In such an implementation, the amountsof the chemicals can be changed to produce a quicker reaction. Forexample, the amounts of sodium bicarbonate and acetic acid can beincreased. In certain implementations, a pressure source can includebetween 0.50 grams and 2.5 grams of sodium bicarbonate. Similarly, apressure source can include between 0.40 grams and 2.2 grams of aceticacid. In a particular example, a pressure source can include 1.5 gramsof sodium bicarbonate and 0.50 grams of acetic acid. As the acetic acidis used in a liquid state, a lower ratio (as compared to the totalamount of chemicals used in the reaction) of acetic acid can be used ascompared to the ratio of the solid sodium bicarbonate. By including ahigher ratio of the sodium bicarbonate, the chances are increased thatthe acetic acid will fully react with the sodium bicarbonate, therebymaximizing the amount of carbon dioxide gas that can be produced by theamount of acetic acid used. Any excess sodium bicarbonate will remain inthe pressure source in an unreacted state.

As noted above, the internal volume that the pressurized fluid isintended to fill can vary between implementation as well. For example,as noted above, the total internal volume can vary between 10-50 cm³.When the internal volume is less than the volume as used in the abovecalculations (25 cm³), the amount of the individual chemicals can bereduced as a lesser amount of pressurized fluid may be used. Conversely,when the internal volume is greater than the volume as used in the abovecalculations, the amount of the individual chemicals can be increased asa greater amount of pressurized fluid may be used. For example, apressure source can include between 0.25 grams and 5 grams of sodiumbicarbonate. Similarly, a pressure source can include between 0.15 and 4grams of acetic acid.

In addition to changing the quantities of the chemicals used, changingthe chemicals reacting with one another to produce a different gas canbe used to control both the volume and speed of a reaction. Instead ofproducing carbon dioxide, as discussed above, oxygen or nitrogen can begenerated from a chemical reaction.

In some implementations, the pressure source 300 can include a firstchemical 306 and a second chemical 308, wherein the first chemical 306and the second chemical 208 are selected to produce nitrogen gas oroxygen gas.

To produce oxygen gas, the first chemical 306 can be sodium chlorate,potassium perchlorate, potassium permanganate, potassium iodide, ormixtures thereof and the second chemical 308 can be hydrogen peroxide,barium peroxide, iron powder, or mixtures thereof. Yeast can be used asthe first chemical 306 in some implementations. In some implementations,the second chemical 308 is hydrogen peroxide. In some implementations,the second chemical 308 is hydrogen peroxide and the first chemical 306can be one or a mixture of potassium iodide, yeast, and potassiumpermanganate.

To produce nitrogen gas, the first chemical 306 can be an ammoniumcompound and the second chemical 308 can be a chemical that reacts withthe ammonium compound to produce nitrogen gas. Examples of the ammoniumcompound include ammonium nitrite, ammonium nitrate, ammonium, chloride,ammonium dichromate, ammonium hydroxide, or mixtures thereof. Examplesthe second chemical 308 can be sodium nitrite, potassium nitrite,calcium nitrite, or other nitrite compound.

Nitrogen gas can also be produced by the reaction of hypochlorites orhypobromites on ammonia, reduction of nitric and/or nitrous oxides,reaction of ammonia gas with a nitrite compound, or combinations ofthese reactions.

For example, the chemical reaction can include mixing an aqueousperoxide such as hydrogen peroxide with a metallic salt such aspotassium iodide to produce oxygen gas. Such a reaction results in thecatalyzed decomposition of the hydrogen peroxide to produce water andoxygen gas. Specifically, the hydrogen peroxide reacts with iodide ionsfrom the potassium iodide to produce the oxygen gas. For example, thereactions can be represented as:

H₂O₂+I⁻→H₂O+IO⁻  (4)

H₂O₂+IO⁻→H₂O+O₂+I⁻  (5)

where H₂O₂ is hydrogen peroxide, I⁺ is an iodide ion, H₂O is water, IO⁻is a hypoiodite ion, and O₂ is oxygen gas.

As noted above, a specific amount of pressurized fluid can be createdduring the chemical reaction, the pressurized fluid being directed toindividual gel reservoirs to facilitate release of conductive gel storedtherein. For example, the pressurized fluid can be configured to fill aninternal volume of 10 cm³ to a pressure of approximately 50 psi (e.g., a35 psi pressure to facilitate release of the conductive gel from the gelreservoirs plus a 15 psi safety buffer to account for any unreactedchemicals or other potential complications during the chemicalreaction). In the above example chemical reaction, the resultingpressurized fluid is oxygen gas, which has a molar mass of 32.00 g/molat room temperature (e.g., approximately 295K). As such, based upon thedesired pressure (50 psi at standard atmospheric pressure), the internalvolume (25 cm³), and the molar mass of the carbon dioxide, an amount ofcarbon dioxide to be produced during the chemical reaction can becalculated using the ideal gas law.

Substituting the values as noted above into the ideal gas law, theresulting equation is:

(50 psi at 1 atm)(25 cm³)=(mass of O₂/32.00 g/mol)(8.31441 J K⁻¹mol⁻¹)(295K).

Converting both pressure and volume to appropriate units (Pascal andcubic meters respectively) results in:

(344737 pa)(0.000025 m³)=(mass of O₂/32.00 g/mol)(8.31441 J K⁻¹mol⁻¹)(295K).

Solving the above equation gives a mass of 0.11 g of O₂ to be produced.Such a mass of O₂ will result in the desired 50 psi in the internalvolume of 25 cm³. O₂ has a density of 1.43 g/L in its gaseous state. Assuch, the above equation results in 0.077 liters of O₂. Thus, a chemicalreaction that produces 0.077 liters of O₂ will result in a 50 psipressure in the internal volume of 25 cm³.

The amount of hydrogen peroxide and potassium iodide to include can bedetermined based upon the resulting amount of O₂ produced. As notedabove, 0.11 g of O₂ produces a pressure that will result in release ofthe conductive gel from the conductive gel reservoirs as describedabove. As noted above, O₂ has a molar mass of 32.00 g/mol. As such, 0.11g equals approximate 0.0046 moles of O₂. As such, approximately 0.0046moles of both potassium iodide and hydrogen peroxide should be includedin the reaction. Hydrogen peroxide has a molar mass of 34.015 g/mol. Assuch, approximately 0.0046 moles of hydrogen peroxide is 0.16 grams.Potassium iodide has a molar mass of 166.00 g/mol. As such,approximately 0.0046 moles of potassium iodide is 0.76 grams. As such,to produce 0.11 grams of O₂, at least 0.16 grams of hydrogen peroxideshould fully react with 0.76 grams of potassium iodide.

Thus, in certain implementations of the pressure sources 300 and 400 asdescribed above, approximately 0.76 grams of potassium iodide (e.g., ina powdered form) can be used for the first chemical, and approximately0.16 grams of hydrogen peroxide can be used for the second chemical.Thus, in a particular example referring to pressure source 300 as shownin FIG. 3, approximately 0.76 grams of powdered potassium iodide can beloaded into the case 302. Similarly, approximately 0.16 grams ofhydrogen peroxide can be loaded into isolating container 310.

See Table 2 for calculations showing the amounts of oxygen gas ornitrogen gas needed for resulting pressures ranging from 1 psi to 100psi for a volume of 25 cm³. The reactant amounts can then be calculatedusing the values of nitrogen gas or oxygen gas needed from Table 2 in amanner similar to the calculations in Table 1.

Tables 3-22 show amounts of carbon dioxide, nitrogen, and oxygen gasneeded for volumes ranging from 5 cm³ to 100 cm³.

It will be understood that the implementations obtained from scaling upor scaling down (i.e., changing pressure, volume, or temperature) theimplementations exemplified in the Tables attached hereto (but not shownin the Tables) are included in this disclosure.

When the controller, e.g., medical device controller 120, triggers arelease of the conductive gel, the wire 312 can be heated, therebycausing a structural compromise of the isolating container 310 (e.g.,the wire 312 melts a hole in isolating container 310). The hydrogenperoxide can then be released from the isolating container 310. Incertain implementations, leaf springs 314 can provide an external forceagainst the isolating container 310, causing quicker release of thehydrogen peroxide. The hydrogen peroxide can then mix with the potassiumiodide in the case 302, causing catalytic decomposition of the hydrogenperoxide into water and oxygen gas. The oxygen gas can be directed outof the case 302 via the exit port 304. The oxygen gas can then bedirected by one or more fluid conduits, such as fluid channel 230, tothe gel reservoirs.

As described above, the speed of the reaction can be a criticalconsideration. In order to adjust the reaction speed, the amounts ofhydrogen peroxide and potassium iodide can be increased. In certainimplementations, a pressure source can include between 0.20 grams and2.5 grams of hydrogen peroxide. Similarly, a pressure source can includebetween 0.80 grams and 5.0 grams of potassium iodide. In a particularexample, a pressure source can include 0.5 grams of hydrogen peroxideand 1.50 grams of potassium iodide.

TABLE 1 Moles of Amount of R n (number Moles of Amount sodim sodiumPres- Pres- (ideal gas T of moles of MW of Amount Acetic of Aceticbicar- bicar- sure sure Volume Volume constant − (Kel- gas) = (pV)/ CO2of CO2 Acid Acid bonate bonate (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (mol) (g) (mol) (g) 1 6894.76 25 0.000025 8.3144598 2950.00007028 44.0095 0.003093 0.00007028 0.004217 0.00007028 0.005903128 534473.79 25 0.000025 8.3144598 295 0.00035138 44.0095 0.0154640.00035138 0.021083 0.00035138 0.029515642 10 68947.57 25 0.0000258.3144598 295 0.00070275 44.0095 0.030928 0.00070275 0.042165 0.000702750.059031283 15 103421.36 25 0.000025 8.3144598 295 0.00105413 44.00950.046392 0.00105413 0.063248 0.00105413 0.088546925 20 137895.15 250.000025 8.3144598 295 0.00140551 44.0095 0.061856 0.00140551 0.084330.00140551 0.118062566 25 172368.93 25 0.000025 8.3144598 295 0.0017568844.0095 0.07732 0.00175688 0.105413 0.00175688 0.147578208 30 206842.7225 0.000025 8.3144598 295 0.00210826 44.0095 0.092783 0.002108260.126496 0.00210826 0.177093849 35 241316.50 25 0.000025 8.3144598 2950.00245964 44.0095 0.108247 0.00245964 0.147578 0.00245964 0.20660949140 275790.29 25 0.000025 8.3144598 295 0.00281101 44.0095 0.1237110.00281101 0.168661 0.00281101 0.236125132 45 310264.08 25 0.0000258.3144598 295 0.00316239 44.0095 0.139175 0.00316239 0.189743 0.003162390.265640774 50 344737.86 25 0.000025 8.3144598 295 0.00351377 44.00950.154639 0.00351377 0.210826 0.00351377 0.295156415 55 379211.65 250.000025 8.3144598 295 0.00386514 44.0095 0.170103 0.00386514 0.2319090.00386514 0.324672057 60 413685.44 25 0.000025 8.3144598 295 0.0042165244.0095 0.185567 0.00421652 0.252991 0.00421652 0.354187698 65 448159.2225 0.000025 8.3144598 295 0.00456790 44.0095 0.201031 0.004567900.274074 0.00456790 0.38370334 70 482633.01 25 0.000025 8.3144598 2950.00491927 44.0095 0.216495 0.00491927 0.295156 0.00491927 0.41321898275 517106.80 25 0.000025 8.3144598 295 0.00527065 44.0095 0.2319590.00491927 0.295156 0.00491927 0.413218982 80 551580.58 25 0.0000258.3144598 295 0.00562203 44.0095 0.247423 0.00491927 0.295156 0.004919270.413218982 85 586054.37 25 0.000025 8.3144598 295 0.00597340 44.00950.262887 0.00491927 0.295156 0.00491927 0.413218982 90 620528.16 250.000025 8.3144598 295 0.00632478 44.0095 0.27835 0.00491927 0.2951560.00491927 0.413218982 95 655001.94 25 0.000025 8.3144598 295 0.0066761644.0095 0.293814 0.00491927 0.295156 0.00491927 0.413218982 100689475.73 25 0.000025 8.3144598 295 0.00702753 44.0095 0.3092780.00491927 0.295156 0.00491927 0.413218982

TABLE 2 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount sure sure Volume Volume constant − (Kel- gas) = (pV)/ N2 of N2O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin) (RT) (g/mol) (g) (g/mol)(g) 1 6894.76 25 0.000025 8.3144598 295 0.00007028 28 0.00196771 320.0022488 5 34473.79 25 0.000025 8.3144598 295 0.00035138 28 0.0098385532 0.0112441 10 68947.57 25 0.000025 8.3144598 295 0.00070275 280.01967709 32 0.0224881 15 103421.36 25 0.000025 8.3144598 2950.00105413 28 0.02951564 32 0.0337322 20 137895.15 25 0.000025 8.3144598295 0.00140551 28 0.03935419 32 0.0449762 25 172368.93 25 0.0000258.3144598 295 0.00175688 28 0.04919274 32 0.0562203 30 206842.72 250.000025 8.3144598 295 0.00210826 28 0.05903128 32 0.0674643 35241316.50 25 0.000025 8.3144598 295 0.00245964 28 0.06886983 320.0787084 40 275790.29 25 0.000025 8.3144598 295 0.00281101 280.07870838 32 0.0899524 45 310264.08 25 0.000025 8.3144598 2950.00316239 28 0.08854692 32 0.1011965 50 344737.86 25 0.000025 8.3144598295 0.00351377 28 0.09838547 32 0.1124405 55 379211.65 25 0.0000258.3144598 295 0.00386514 28 0.10822402 32 0.1236846 60 413685.44 250.000025 8.3144598 295 0.00421652 28 0.11806257 32 0.1349286 65448159.22 25 0.000025 8.3144598 295 0.00456790 28 0.12790111 320.1461727 70 482633.01 25 0.000025 8.3144598 295 0.00491927 280.13773966 32 0.1574168 75 517106.80 25 0.000025 8.3144598 2950.00527065 28 0.14757821 32 0.1686608 80 551580.58 25 0.000025 8.3144598295 0.00562203 28 0.15741675 32 0.1799049 85 586054.37 25 0.0000258.3144598 295 0.00597340 28 0.1672553 32 0.1911489 90 620528.16 250.000025 8.3144598 295 0.00632478 28 0.17709385 32 0.202393 95 655001.9425 0.000025 8.3144598 295 0.00667616 28 0.1869324 32 0.213637 100689475.73 25 0.000025 8.3144598 295 0.00702753 28 0.19677094 320.2248811

TABLE 3 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount MW of Amount sure sure Volume Volume constant − (Kel- gas) =(pV)/ CO2 of CO2 N2 of N2 O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (g/mol) (g) (g/mol) (g) 5 34473.79 5 0.000005 8.3144598295 0.00007028 44.0095 0.003093 28 0.001968 32 0.002249 10 68947.57 50.000005 8.3144598 295 0.00014055 44.0095 0.006186 28 0.003935 320.004498 15 103421.36 5 0.000005 8.3144598 295 0.00021083 44.00950.009278 28 0.005903 32 0.006746 20 137895.15 5 0.000005 8.3144598 2950.00028110 44.0095 0.012371 28 0.007871 32 0.008995 25 172368.93 50.000005 8.3144598 295 0.00035138 44.0095 0.015464 28 0.009839 320.011244 30 206842.72 5 0.000005 8.3144598 295 0.00042165 44.00950.018557 28 0.011806 32 0.013493 35 241316.50 5 0.000005 8.3144598 2950.00049193 44.0095 0.021649 28 0.013774 32 0.015742 40 275790.29 50.000005 8.3144598 295 0.00056220 44.0095 0.024742 28 0.015742 320.01799 45 310264.08 5 0.000005 8.3144598 295 0.00063248 44.00950.027835 28 0.017709 32 0.020239 50 344737.86 5 0.000005 8.3144598 2950.00070275 44.0095 0.030928 28 0.019677 32 0.022488 55 379211.65 50.000005 8.3144598 295 0.00077303 44.0095 0.034021 28 0.021645 320.024737 60 413685.44 5 0.000005 8.3144598 295 0.00084330 44.00950.037113 28 0.023613 32 0.026986 65 448159.22 5 0.000005 8.3144598 2950.00091358 44.0095 0.040206 28 0.02558 32 0.029235 70 482633.01 50.000005 8.3144598 295 0.00098385 44.0095 0.043299 28 0.027548 320.031483 75 517106.80 5 0.000005 8.3144598 295 0.00105413 44.00950.046392 28 0.029516 32 0.033732

TABLE 4 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount MW of Amount sure sure Volume Volume constant − (Kel- gas) =(pV)/ CO2 of CO2 N2 of N2 O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (g/mol) (g) (g/mol) (g) 5 34473.79 10 0.00001 8.3144598295 0.00014055 44.0095 0.006186 28 0.003935 32 0.004498 10 68947.57 100.00001 8.3144598 295 0.00028110 44.0095 0.012371 28 0.007871 320.008995 15 103421.36 10 0.00001 8.3144598 295 0.00042165 44.00950.018557 28 0.011806 32 0.013493 20 137895.15 10 0.00001 8.3144598 2950.00056220 44.0095 0.024742 28 0.015742 32 0.01799 25 172368.93 100.00001 8.3144598 295 0.00070275 44.0095 0.030928 28 0.019677 320.022488 30 206842.72 10 0.00001 8.3144598 295 0.00084330 44.00950.037113 28 0.023613 32 0.026986 35 241316.50 10 0.00001 8.3144598 2950.00098385 44.0095 0.043299 28 0.027548 32 0.031483 40 275790.29 100.00001 8.3144598 295 0.00112441 44.0095 0.049485 28 0.031483 320.035981 45 310264.08 10 0.00001 8.3144598 295 0.00126496 44.00950.05567 28 0.035419 32 0.040479 50 344737.86 10 0.00001 8.3144598 2950.00140551 44.0095 0.061856 28 0.039354 32 0.044976 55 379211.65 100.00001 8.3144598 295 0.00154606 44.0095 0.068041 28 0.04329 32 0.04947460 413685.44 10 0.00001 8.3144598 295 0.00168661 44.0095 0.074227 280.047225 32 0.053971 65 448159.22 10 0.00001 8.3144598 295 0.0018271644.0095 0.080412 28 0.05116 32 0.058469 70 482633.01 10 0.000018.3144598 295 0.00196771 44.0095 0.086598 28 0.055096 32 0.062967 75517106.80 10 0.00001 8.3144598 295 0.00210826 44.0095 0.092783 280.059031 32 0.067464

TABLE 5 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount MW of Amount sure sure Volume Volume constant − (Kel- gas) =(pV)/ CO2 of CO2 N2 of N2 O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (g/mol) (g) (g/mol) (g) 5 34473.79 15 0.0000158.3144598 295 0.00021083 44.0095 0.009278 28 0.005903 32 0.006746 1068947.57 15 0.000015 8.3144598 295 0.00042165 44.0095 0.018557 280.011806 32 0.013493 15 103421.36 15 0.000015 8.3144598 295 0.0006324844.0095 0.027835 28 0.017709 32 0.020239 20 137895.15 15 0.0000158.3144598 295 0.00084330 44.0095 0.037113 28 0.023613 32 0.026986 25172368.93 15 0.000015 8.3144598 295 0.00105413 44.0095 0.046392 280.029516 32 0.033732 30 206842.72 15 0.000015 8.3144598 295 0.0012649644.0095 0.05567 28 0.035419 32 0.040479 35 241316.50 15 0.0000158.3144598 295 0.00147578 44.0095 0.064948 28 0.041322 32 0.047225 40275790.29 15 0.000015 8.3144598 295 0.00168661 44.0095 0.074227 280.047225 32 0.053971 45 310264.08 15 0.000015 8.3144598 295 0.0018974344.0095 0.083505 28 0.053128 32 0.060718 50 344737.86 15 0.0000158.3144598 295 0.00210826 44.0095 0.092783 28 0.059031 32 0.067464 55379211.65 15 0.000015 8.3144598 295 0.00231909 44.0095 0.102062 280.064934 32 0.074211 60 413685.44 15 0.000015 8.3144598 295 0.0025299144.0095 0.11134 28 0.070838 32 0.080957 65 448159.22 15 0.0000158.3144598 295 0.00274074 44.0095 0.120619 28 0.076741 32 0.087704 70482633.01 15 0.000015 8.3144598 295 0.00295156 44.0095 0.129897 280.082644 32 0.09445 75 517106.80 15 0.000015 8.3144598 295 0.0031623944.0095 0.139175 28 0.088547 32 0.101196

TABLE 6 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount MW of Amount sure sure Volume Volume constant − (Kel- gas) =(pV)/ CO2 of CO2 N2 of N2 O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (g/mol) (g) (g/mol) (g) 5 34473.79 20 0.00002 8.3144598295 0.00028110 44.0095 0.012371 28 0.007871 32 0.008995 10 68947.57 200.00002 8.3144598 295 0.00056220 44.0095 0.024742 28 0.015742 32 0.0179915 103421.36 20 0.00002 8.3144598 295 0.00084330 44.0095 0.037113 280.023613 32 0.026986 20 137895.15 20 0.00002 8.3144598 295 0.0011244144.0095 0.049485 28 0.031483 32 0.035981 25 172368.93 20 0.000028.3144598 295 0.00140551 44.0095 0.061856 28 0.039354 32 0.044976 30206842.72 20 0.00002 8.3144598 295 0.00168661 44.0095 0.074227 280.047225 32 0.053971 35 241316.50 20 0.00002 8.3144598 295 0.0019677144.0095 0.086598 28 0.055096 32 0.062967 40 275790.29 20 0.000028.3144598 295 0.00224881 44.0095 0.098969 28 0.062967 32 0.071962 45310264.08 20 0.00002 8.3144598 295 0.00252991 44.0095 0.11134 280.070838 32 0.080957 50 344737.86 20 0.00002 8.3144598 295 0.0028110144.0095 0.123711 28 0.078708 32 0.089952 55 379211.65 20 0.000028.3144598 295 0.00309211 44.0095 0.136082 28 0.086579 32 0.098948 60413685.44 20 0.00002 8.3144598 295 0.00337322 44.0095 0.148454 280.09445 32 0.107943 65 448159.22 20 0.00002 8.3144598 295 0.0036543244.0095 0.160825 28 0.102321 32 0.116938 70 482633.01 20 0.000028.3144598 295 0.00393542 44.0095 0.173196 28 0.110192 32 0.125933 75517106.80 20 0.00002 8.3144598 295 0.00421652 44.0095 0.185567 280.118063 32 0.134929

TABLE 7 R n (number Pres- Pres- (ideal gas T of moles of MW of Amount MWof Amount MW of Amount sure sure Volume Volume constant − (Kel- gas) =(pV)/ CO2 of CO2 N2 of N2 O2 of O2 (psi) (pa) (cm3) (m3) J/K · mol) vin)(RT) (g/mol) (g) (g/mol) (g) (g/mol) (g) 5 34473.79 25 0.0000258.3144598 295 0.00035138 44.0095 0.015464 28 0.009839 32 0.011244 1068947.57 25 0.000025 8.3144598 295 0.00070275 44.0095 0.030928 280.019677 32 0.022488 15 103421.36 25 0.000025 8.3144598 295 0.0010541344.0095 0.046392 28 0.029516 32 0.033732 20 137895.15 25 0.0000258.3144598 295 0.00140551 44.0095 0.061856 28 0.039354 32 0.044976 25172368.93 25 0.000025 8.3144598 295 0.00175688 44.0095 0.07732 280.049193 32 0.05622 30 206842.72 25 0.000025 8.3144598 295 0.0021082644.0095 0.092783 28 0.059031 32 0.067464 35 241316.50 25 0.0000258.3144598 295 0.00245964 44.0095 0.108247 28 0.06887 32 0.078708 40275790.29 25 0.000025 8.3144598 295 0.00281101 44.0095 0.123711 280.078708 32 0.089952 45 310264.08 25 0.000025 8.3144598 295 0.0031623944.0095 0.139175 28 0.088547 32 0.101196 50 344737.86 25 0.0000258.3144598 295 0.00351377 44.0095 0.154639 28 0.098385 32 0.112441 55379211.65 25 0.000025 8.3144598 295 0.00386514 44.0095 0.170103 280.108224 32 0.123685 60 413685.44 25 0.000025 8.3144598 295 0.0042165244.0095 0.185567 28 0.118063 32 0.134929 65 448159.22 25 0.0000258.3144598 295 0.00456790 44.0095 0.201031 28 0.127901 32 0.146173 70482633.01 25 0.000025 8.3144598 295 0.00491927 44.0095 0.216495 280.13774 32 0.157417 75 517106.80 25 0.000025 8.3144598 295 0.0052706544.0095 0.231959 28 0.147578 32 0.168661

TABLE 8 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 30 0.00003 8.3144598295 0.00042165 44.0095 0.018557 28 0.011806 32 0.013493 10 68947.57 300.00003 8.3144598 295 0.00084330 44.0095 0.037113 28 0.023613 320.026986 15 103421.36 30 0.00003 8.3144598 295 0.00126496 44.00950.05567 28 0.035419 32 0.040479 20 137895.15 30 0.00003 8.3144598 2950.00168661 44.0095 0.074227 28 0.047225 32 0.053971 25 172368.93 300.00003 8.3144598 295 0.00210826 44.0095 0.092783 28 0.059031 320.067464 30 206842.72 30 0.00003 8.3144598 295 0.00252991 44.00950.11134 28 0.070838 32 0.080957 35 241316.50 30 0.00003 8.3144598 2950.00295156 44.0095 0.129897 28 0.082644 32 0.09445 40 275790.29 300.00003 8.3144598 295 0.00337322 44.0095 0.148454 28 0.09445 32 0.10794345 310264.08 30 0.00003 8.3144598 295 0.00379487 44.0095 0.16701 280.106256 32 0.121436 50 344737.86 30 0.00003 8.3144598 295 0.0042165244.0095 0.185567 28 0.118063 32 0.134929 55 379211.65 30 0.000038.3144598 295 0.00463817 44.0095 0.204124 28 0.129869 32 0.148422 60413685.44 30 0.00003 8.3144598 295 0.00505982 44.0095 0.22268 280.141675 32 0.161914 65 448159.22 30 0.00003 8.3144598 295 0.0054814844.0095 0.241237 28 0.153481 32 0.175407 70 482633.01 30 0.000038.3144598 295 0.00590313 44.0095 0.259794 28 0.165288 32 0.1889 75517106.80 30 0.00003 8.3144598 295 0.00632478 44.0095 0.27835 280.177094 32 0.202393

TABLE 9 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 35 0.000035 8.3144598 2950.00049193 44.0095 0.021649 28 0.013774 32 0.015742 10 68947.57 350.000035 8.3144598 295 0.00098385 44.0095 0.043299 28 0.027548 320.031483 15 103421.36 35 0.000035 8.3144598 295 0.00147578 44.00950.064948 28 0.041322 32 0.047225 20 137895.15 35 0.000035 8.3144598 2950.00196771 44.0095 0.086598 28 0.055096 32 0.062967 25 172368.93 350.000035 8.3144598 295 0.00245964 44.0095 0.108247 28 0.06887 320.078708 30 206842.72 35 0.000035 8.3144598 295 0.00295156 44.00950.129897 28 0.082644 32 0.09445 35 241316.50 35 0.000035 8.3144598 2950.00344349 44.0095 0.151546 28 0.096418 32 0.110192 40 275790.29 350.000035 8.3144598 295 0.00393542 44.0095 0.173196 28 0.110192 320.125933 45 310264.08 35 0.000035 8.3144598 295 0.00442735 44.00950.194845 28 0.123966 32 0.141675 50 344737.86 35 0.000035 8.3144598 2950.00491927 44.0095 0.216495 28 0.13774 32 0.157417 55 379211.65 350.000035 8.3144598 295 0.00541120 44.0095 0.238144 28 0.151514 320.173158 60 413685.44 35 0.000035 8.3144598 295 0.00590313 44.00950.259794 28 0.165288 32 0.1889 65 448159.22 35 0.000035 8.3144598 2950.00639506 44.0095 0.281443 28 0.179062 32 0.204642 70 482633.01 350.000035 8.3144598 295 0.00688698 44.0095 0.303093 28 0.192836 320.220383 75 517106.80 35 0.000035 8.3144598 295 0.00737891 44.00950.324742 28 0.206609 32 0.236125

TABLE 10 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 40 0.00004 8.3144598295 0.00056220 44.0095 0.024742 28 0.015742 32 0.01799 10 68947.57 400.00004 8.3144598 295 0.00112441 44.0095 0.049485 28 0.031483 320.035981 15 103421.36 40 0.00004 8.3144598 295 0.00168661 44.00950.074227 28 0.047225 32 0.053971 20 137895.15 40 0.00004 8.3144598 2950.00224881 44.0095 0.098969 28 0.062967 32 0.071962 25 172368.93 400.00004 8.3144598 295 0.00281101 44.0095 0.123711 28 0.078708 320.089952 30 206842.72 40 0.00004 8.3144598 295 0.00337322 44.00950.148454 28 0.09445 32 0.107943 35 241316.50 40 0.00004 8.3144598 2950.00393542 44.0095 0.173196 28 0.110192 32 0.125933 40 275790.29 400.00004 8.3144598 295 0.00449762 44.0095 0.197938 28 0.125933 320.143924 45 310264.08 40 0.00004 8.3144598 295 0.00505982 44.00950.22268 28 0.141675 32 0.161914 50 344737.86 40 0.00004 8.3144598 2950.00562203 44.0095 0.247423 28 0.157417 32 0.179905 55 379211.65 400.00004 8.3144598 295 0.00618423 44.0095 0.272165 28 0.173158 320.197895 60 413685.44 40 0.00004 8.3144598 295 0.00674643 44.00950.296907 28 0.1889 32 0.215886 65 448159.22 40 0.00004 8.3144598 2950.00730864 44.0095 0.321649 28 0.204642 32 0.233876 70 482633.01 400.00004 8.3144598 295 0.00787084 44.0095 0.346392 28 0.220383 320.251867 75 517106.80 40 0.00004 8.3144598 295 0.00843304 44.00950.371134 28 0.236125 32 0.269857

TABLE 11 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 45 0.000045 8.3144598 2950.00063248 44.0095 0.027835 28 0.017709 32 0.020239 10 68947.57 450.000045 8.3144598 295 0.00126496 44.0095 0.05567 28 0.035419 320.040479 15 103421.36 45 0.000045 8.3144598 295 0.00189743 44.00950.083505 28 0.053128 32 0.060718 20 137895.15 45 0.000045 8.3144598 2950.00252991 44.0095 0.11134 28 0.070838 32 0.080957 25 172368.93 450.000045 8.3144598 295 0.00316239 44.0095 0.139175 28 0.088547 320.101196 30 206842.72 45 0.000045 8.3144598 295 0.00379487 44.00950.16701 28 0.106256 32 0.121436 35 241316.50 45 0.000045 8.3144598 2950.00442735 44.0095 0.194845 28 0.123966 32 0.141675 40 275790.29 450.000045 8.3144598 295 0.00505982 44.0095 0.22268 28 0.141675 320.161914 45 310264.08 45 0.000045 8.3144598 295 0.00569230 44.00950.250515 28 0.159384 32 0.182154 50 344737.86 45 0.000045 8.3144598 2950.00632478 44.0095 0.27835 28 0.177094 32 0.202393 55 379211.65 450.000045 8.3144598 295 0.00695726 44.0095 0.306185 28 0.194803 320.222632 60 413685.44 45 0.000045 8.3144598 295 0.00758974 44.00950.334021 28 0.212513 32 0.242872 65 448159.22 45 0.000045 8.3144598 2950.00822221 44.0095 0.361856 28 0.230222 32 0.263111 70 482633.01 450.000045 8.3144598 295 0.00885469 44.0095 0.389691 28 0.247931 320.28335 75 517106.80 45 0.000045 8.3144598 295 0.00948717 44.00950.417526 28 0.265641 32 0.303589

TABLE 12 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 50 0.00005 8.3144598295 0.00070275 44.0095 0.030928 28 0.019677 32 0.022488 10 68947.57 500.00005 8.3144598 295 0.00140551 44.0095 0.061856 28 0.039354 320.044976 15 103421.36 50 0.00005 8.3144598 295 0.00210826 44.00950.092783 28 0.059031 32 0.067464 20 137895.15 50 0.00005 8.3144598 2950.00281101 44.0095 0.123711 28 0.078708 32 0.089952 25 172368.93 500.00005 8.3144598 295 0.00351377 44.0095 0.154639 28 0.098385 320.112441 30 206842.72 50 0.00005 8.3144598 295 0.00421652 44.00950.185567 28 0.118063 32 0.134929 35 241316.50 50 0.00005 8.3144598 2950.00491927 44.0095 0.216495 28 0.13774 32 0.157417 40 275790.29 500.00005 8.3144598 295 0.00562203 44.0095 0.247423 28 0.157417 320.179905 45 310264.08 50 0.00005 8.3144598 295 0.00632478 44.00950.27835 28 0.177094 32 0.202393 50 344737.86 50 0.00005 8.3144598 2950.00702753 44.0095 0.309278 28 0.196771 32 0.224881 55 379211.65 500.00005 8.3144598 295 0.00773029 44.0095 0.340206 28 0.216448 320.247369 60 413685.44 50 0.00005 8.3144598 295 0.00843304 44.00950.371134 28 0.236125 32 0.269857 65 448159.22 50 0.00005 8.3144598 2950.00913579 44.0095 0.402062 28 0.255802 32 0.292345 70 482633.01 500.00005 8.3144598 295 0.00983855 44.0095 0.43299 28 0.275479 32 0.31483475 517106.80 50 0.00005 8.3144598 295 0.01054130 44.0095 0.463917 280.295156 32 0.337322

TABLE 13 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 55 0.000055 8.3144598 2950.00077303 44.0095 0.034021 28 0.021645 32 0.024737 10 68947.57 550.000055 8.3144598 295 0.00154606 44.0095 0.068041 28 0.04329 320.049474 15 103421.36 55 0.000055 8.3144598 295 0.00231909 44.00950.102062 28 0.064934 32 0.074211 20 137895.15 55 0.000055 8.3144598 2950.00309211 44.0095 0.136082 28 0.086579 32 0.098948 25 172368.93 550.000055 8.3144598 295 0.00386514 44.0095 0.170103 28 0.108224 320.123685 30 206842.72 55 0.000055 8.3144598 295 0.00463817 44.00950.204124 28 0.129869 32 0.148422 35 241316.50 55 0.000055 8.3144598 2950.00541120 44.0095 0.238144 28 0.151514 32 0.173158 40 275790.29 550.000055 8.3144598 295 0.00618423 44.0095 0.272165 28 0.173158 320.197895 45 310264.08 55 0.000055 8.3144598 295 0.00695726 44.00950.306185 28 0.194803 32 0.222632 50 344737.86 55 0.000055 8.3144598 2950.00773029 44.0095 0.340206 28 0.216448 32 0.247369 55 379211.65 550.000055 8.3144598 295 0.00850332 44.0095 0.374227 28 0.238093 320.272106 60 413685.44 55 0.000055 8.3144598 295 0.00927634 44.00950.408247 28 0.259738 32 0.296843 65 448159.22 55 0.000055 8.3144598 2950.01004937 44.0095 0.442268 28 0.281382 32 0.32158 70 482633.01 550.000055 8.3144598 295 0.01082240 44.0095 0.476288 28 0.303027 320.346317 75 517106.80 55 0.000055 8.3144598 295 0.01159543 44.00950.510309 28 0.324672 32 0.371054

TABLE 14 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 60 0.00006 8.3144598295 0.00084330 44.0095 0.037113 28 0.023613 32 0.026986 10 68947.57 600.00006 8.3144598 295 0.00168661 44.0095 0.074227 28 0.047225 320.053971 15 103421.36 60 0.00006 8.3144598 295 0.00252991 44.00950.11134 28 0.070838 32 0.080957 20 137895.15 60 0.00006 8.3144598 2950.00337322 44.0095 0.148454 28 0.09445 32 0.107943 25 172368.93 600.00006 8.3144598 295 0.00421652 44.0095 0.185567 28 0.118063 320.134929 30 206842.72 60 0.00006 8.3144598 295 0.00505982 44.00950.22268 28 0.141675 32 0.161914 35 241316.50 60 0.00006 8.3144598 2950.00590313 44.0095 0.259794 28 0.165288 32 0.1889 40 275790.29 600.00006 8.3144598 295 0.00674643 44.0095 0.296907 28 0.1889 32 0.21588645 310264.08 60 0.00006 8.3144598 295 0.00758974 44.0095 0.334021 280.212513 32 0.242872 50 344737.86 60 0.00006 8.3144598 295 0.0084330444.0095 0.371134 28 0.236125 32 0.269857 55 379211.65 60 0.000068.3144598 295 0.00927634 44.0095 0.408247 28 0.259738 32 0.296843 60413685.44 60 0.00006 8.3144598 295 0.01011965 44.0095 0.445361 280.28335 32 0.323829 65 448159.22 60 0.00006 8.3144598 295 0.0109629544.0095 0.482474 28 0.306963 32 0.350814 70 482633.01 60 0.000068.3144598 295 0.01180626 44.0095 0.519587 28 0.330575 32 0.3778 75517106.80 60 0.00006 8.3144598 295 0.01264956 44.0095 0.556701 280.354188 32 0.404786

TABLE 15 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 65 0.000065 8.3144598 2950.00091358 44.0095 0.040206 28 0.02558 32 0.029235 10 68947.57 650.000065 8.3144598 295 0.00182716 44.0095 0.080412 28 0.05116 320.058469 15 103421.36 65 0.000065 8.3144598 295 0.00274074 44.00950.120619 28 0.076741 32 0.087704 20 137895.15 65 0.000065 8.3144598 2950.00365432 44.0095 0.160825 28 0.102321 32 0.116938 25 172368.93 650.000065 8.3144598 295 0.00456790 44.0095 0.201031 28 0.127901 320.146173 30 206842.72 65 0.000065 8.3144598 295 0.00548148 44.00950.241237 28 0.153481 32 0.175407 35 241316.50 65 0.000065 8.3144598 2950.00639506 44.0095 0.281443 28 0.179062 32 0.204642 40 275790.29 650.000065 8.3144598 295 0.00730864 44.0095 0.321649 28 0.204642 320.233876 45 310264.08 65 0.000065 8.3144598 295 0.00822221 44.00950.361856 28 0.230222 32 0.263111 50 344737.86 65 0.000065 8.3144598 2950.00913579 44.0095 0.402062 28 0.255802 32 0.292345 55 379211.65 650.000065 8.3144598 295 0.01004937 44.0095 0.442268 28 0.281382 320.32158 60 413685.44 65 0.000065 8.3144598 295 0.01096295 44.00950.482474 28 0.306963 32 0.350814 65 448159.22 65 0.000065 8.3144598 2950.01187653 44.0095 0.52268 28 0.332543 32 0.380049 70 482633.01 650.000065 8.3144598 295 0.01279011 44.0095 0.562886 28 0.358123 320.409284 75 517106.80 65 0.000065 8.3144598 295 0.01370369 44.00950.603093 28 0.383703 32 0.438518

TABLE 16 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 70 0.00007 8.3144598295 0.00098385 44.0095 0.043299 28 0.027548 32 0.031483 10 68947.57 700.00007 8.3144598 295 0.00196771 44.0095 0.086598 28 0.055096 320.062967 15 103421.36 70 0.00007 8.3144598 295 0.00295156 44.00950.129897 28 0.082644 32 0.09445 20 137895.15 70 0.00007 8.3144598 2950.00393542 44.0095 0.173196 28 0.110192 32 0.125933 25 172368.93 700.00007 8.3144598 295 0.00491927 44.0095 0.216495 28 0.13774 32 0.15741730 206842.72 70 0.00007 8.3144598 295 0.00590313 44.0095 0.259794 280.165288 32 0.1889 35 241316.50 70 0.00007 8.3144598 295 0.0068869844.0095 0.303093 28 0.192836 32 0.220383 40 275790.29 70 0.000078.3144598 295 0.00787084 44.0095 0.346392 28 0.220383 32 0.251867 45310264.08 70 0.00007 8.3144598 295 0.00885469 44.0095 0.389691 280.247931 32 0.28335 50 344737.86 70 0.00007 8.3144598 295 0.0098385544.0095 0.43299 28 0.275479 32 0.314834 55 379211.65 70 0.000078.3144598 295 0.01082240 44.0095 0.476288 28 0.303027 32 0.346317 60413685.44 70 0.00007 8.3144598 295 0.01180626 44.0095 0.519587 280.330575 32 0.3778 65 448159.22 70 0.00007 8.3144598 295 0.0127901144.0095 0.562886 28 0.358123 32 0.409284 70 482633.01 70 0.000078.3144598 295 0.01377397 44.0095 0.606185 28 0.385671 32 0.440767 75517106.80 70 0.00007 8.3144598 295 0.01475782 44.0095 0.649484 280.413219 32 0.47225

TABLE 17 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 75 0.000075 8.3144598 2950.00105413 44.0095 0.046392 28 0.029516 32 0.033732 10 68947.57 750.000075 8.3144598 295 0.00210826 44.0095 0.092783 28 0.059031 320.067464 15 103421.36 75 0.000075 8.3144598 295 0.00316239 44.00950.139175 28 0.088547 32 0.101196 20 137895.15 75 0.000075 8.3144598 2950.00421652 44.0095 0.185567 28 0.118063 32 0.134929 25 172368.93 750.000075 8.3144598 295 0.00527065 44.0095 0.231959 28 0.147578 320.168661 30 206842.72 75 0.000075 8.3144598 295 0.00632478 44.00950.27835 28 0.177094 32 0.202393 35 241316.50 75 0.000075 8.3144598 2950.00737891 44.0095 0.324742 28 0.206609 32 0.236125 40 275790.29 750.000075 8.3144598 295 0.00843304 44.0095 0.371134 28 0.236125 320.269857 45 310264.08 75 0.000075 8.3144598 295 0.00948717 44.00950.417526 28 0.265641 32 0.303589 50 344737.86 75 0.000075 8.3144598 2950.01054130 44.0095 0.463917 28 0.295156 32 0.337322 55 379211.65 750.000075 8.3144598 295 0.01159543 44.0095 0.510309 28 0.324672 320.371054 60 413685.44 75 0.000075 8.3144598 295 0.01264956 44.00950.556701 28 0.354188 32 0.404786 65 448159.22 75 0.000075 8.3144598 2950.01370369 44.0095 0.603093 28 0.383703 32 0.438518 70 482633.01 750.000075 8.3144598 295 0.01475782 44.0095 0.649484 28 0.413219 320.47225 75 517106.80 75 0.000075 8.3144598 295 0.01581195 44.00950.695876 28 0.442735 32 0.505982

TABLE 18 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 80 0.00008 8.3144598295 0.00112441 44.0095 0.049485 28 0.031483 32 0.035981 10 68947.57 800.00008 8.3144598 295 0.00224881 44.0095 0.098969 28 0.062967 320.071962 15 103421.36 80 0.00008 8.3144598 295 0.00337322 44.00950.148454 28 0.09445 32 0.107943 20 137895.15 80 0.00008 8.3144598 2950.00449762 44.0095 0.197938 28 0.125933 32 0.143924 25 172368.93 800.00008 8.3144598 295 0.00562203 44.0095 0.247423 28 0.157417 320.179905 30 206842.72 80 0.00008 8.3144598 295 0.00674643 44.00950.296907 28 0.1889 32 0.215886 35 241316.50 80 0.00008 8.3144598 2950.00787084 44.0095 0.346392 28 0.220383 32 0.251867 40 275790.29 800.00008 8.3144598 295 0.00899524 44.0095 0.395876 28 0.251867 320.287848 45 310264.08 80 0.00008 8.3144598 295 0.01011965 44.00950.445361 28 0.28335 32 0.323829 50 344737.86 80 0.00008 8.3144598 2950.01124405 44.0095 0.494845 28 0.314834 32 0.35981 55 379211.65 800.00008 8.3144598 295 0.01236846 44.0095 0.54433 28 0.346317 32 0.39579160 413685.44 80 0.00008 8.3144598 295 0.01349286 44.0095 0.593814 280.3778 32 0.431772 65 448159.22 80 0.00008 8.3144598 295 0.0146172744.0095 0.643299 28 0.409284 32 0.467753 70 482633.01 80 0.000088.3144598 295 0.01574168 44.0095 0.692783 28 0.440767 32 0.503734 75517106.80 80 0.00008 8.3144598 295 0.01686608 44.0095 0.742268 280.47225 32 0.539715

TABLE 19 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 85 0.000085 8.3144598 2950.00119468 44.0095 0.052577 28 0.033451 32 0.03823 10 68947.57 850.000085 8.3144598 295 0.00238936 44.0095 0.105155 28 0.066902 320.07646 15 103421.36 85 0.000085 8.3144598 295 0.00358404 44.00950.157732 28 0.100353 32 0.114689 20 137895.15 85 0.000085 8.3144598 2950.00477872 44.0095 0.210309 28 0.133804 32 0.152919 25 172368.93 850.000085 8.3144598 295 0.00597340 44.0095 0.262887 28 0.167255 320.191149 30 206842.72 85 0.000085 8.3144598 295 0.00716808 44.00950.315464 28 0.200706 32 0.229379 35 241316.50 85 0.000085 8.3144598 2950.00836277 44.0095 0.368041 28 0.234157 32 0.267608 40 275790.29 850.000085 8.3144598 295 0.00955745 44.0095 0.420618 28 0.267608 320.305838 45 310264.08 85 0.000085 8.3144598 295 0.01075213 44.00950.473196 28 0.30106 32 0.344068 50 344737.86 85 0.000085 8.3144598 2950.01194681 44.0095 0.525773 28 0.334511 32 0.382298 55 379211.65 850.000085 8.3144598 295 0.01314149 44.0095 0.57835 28 0.367962 320.420528 60 413685.44 85 0.000085 8.3144598 295 0.01433617 44.00950.630928 28 0.401413 32 0.458757 65 448159.22 85 0.000085 8.3144598 2950.01553085 44.0095 0.683505 28 0.434864 32 0.496987 70 482633.01 850.000085 8.3144598 295 0.01672553 44.0095 0.736082 28 0.468315 320.535217 75 517106.80 85 0.000085 8.3144598 295 0.01792021 44.00950.78866 28 0.501766 32 0.573447

TABLE 20 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 90 0.00009 8.3144598295 0.00126496 44.0095 0.05567 28 0.035419 32 0.040479 10 68947.57 900.00009 8.3144598 295 0.00252991 44.0095 0.11134 28 0.070838 32 0.08095715 103421.36 90 0.00009 8.3144598 295 0.00379487 44.0095 0.16701 280.106256 32 0.121436 20 137895.15 90 0.00009 8.3144598 295 0.0050598244.0095 0.22268 28 0.141675 32 0.161914 25 172368.93 90 0.000098.3144598 295 0.00632478 44.0095 0.27835 28 0.177094 32 0.202393 30206842.72 90 0.00009 8.3144598 295 0.00758974 44.0095 0.334021 280.212513 32 0.242872 35 241316.50 90 0.00009 8.3144598 295 0.0088546944.0095 0.389691 28 0.247931 32 0.28335 40 275790.29 90 0.000098.3144598 295 0.01011965 44.0095 0.445361 28 0.28335 32 0.323829 45310264.08 90 0.00009 8.3144598 295 0.01138460 44.0095 0.501031 280.318769 32 0.364307 50 344737.86 90 0.00009 8.3144598 295 0.0126495644.0095 0.556701 28 0.354188 32 0.404786 55 379211.65 90 0.000098.3144598 295 0.01391452 44.0095 0.612371 28 0.389606 32 0.445265 60413685.44 90 0.00009 8.3144598 295 0.01517947 44.0095 0.668041 280.425025 32 0.485743 65 448159.22 90 0.00009 8.3144598 295 0.0164444344.0095 0.723711 28 0.460444 32 0.526222 70 482633.01 90 0.000098.3144598 295 0.01770938 44.0095 0.779381 28 0.495863 32 0.5667 75517106.80 90 0.00009 8.3144598 295 0.01897434 44.0095 0.835051 280.531282 32 0.607179

TABLE 21 R (ideal gas n (number of MW of MW MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount of N2 Amount of O2 Amount(psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) of CO2(g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 95 0.000095 8.3144598 2950.00133523 44.0095 0.058763 28 0.037386 32 0.042727 10 68947.57 950.000095 8.3144598 295 0.00267046 44.0095 0.117526 28 0.074773 320.085455 15 103421.36 95 0.000095 8.3144598 295 0.00400569 44.00950.176289 28 0.112159 32 0.128182 20 137895.15 95 0.000095 8.3144598 2950.00534093 44.0095 0.235051 28 0.149546 32 0.17091 25 172368.93 950.000095 8.3144598 295 0.00667616 44.0095 0.293814 28 0.186932 320.213637 30 206842.72 95 0.000095 8.3144598 295 0.00801139 44.00950.352577 28 0.224319 32 0.256364 35 241316.50 95 0.000095 8.3144598 2950.00934662 44.0095 0.41134 28 0.261705 32 0.299092 40 275790.29 950.000095 8.3144598 295 0.01068185 44.0095 0.470103 28 0.299092 320.341819 45 310264.08 95 0.000095 8.3144598 295 0.01201708 44.00950.528866 28 0.336478 32 0.384547 50 344737.86 95 0.000095 8.3144598 2950.01335231 44.0095 0.587629 28 0.373865 32 0.427274 55 379211.65 950.000095 8.3144598 295 0.01468755 44.0095 0.646392 28 0.411251 320.470001 60 413685.44 95 0.000095 8.3144598 295 0.01602278 44.00950.705154 28 0.448638 32 0.512729 65 448159.22 95 0.000095 8.3144598 2950.01735801 44.0095 0.763917 28 0.486024 32 0.555456 70 482633.01 950.000095 8.3144598 295 0.01869324 44.0095 0.82268 28 0.523411 320.598184 75 517106.80 95 0.000095 8.3144598 295 0.02002847 44.00950.881443 28 0.560797 32 0.640911

TABLE 22 R (ideal gas n (number of MW of MW Pressure Pressure VolumeVolume constant- T moles of gas) = CO2 Amount MW of N2 Amount of O2Amount (psi) (pa) (cm3) (m3) J/K · mol) (Kelvin) (pV)/(RT) (g/mol) ofCO2 (g/mol) of N2 (g) (g/mol) of O2 (g) 5 34473.79 100 0.0001 8.3144598295 0.00140551 44.0095 0.061856 28 0.039354 32 0.044976 10 68947.57 1000.0001 8.3144598 295 0.00281101 44.0095 0.123711 28 0.078708 32 0.08995215 103421.36 100 0.0001 8.3144598 295 0.00421652 44.0095 0.185567 280.118063 32 0.134929 20 137895.15 100 0.0001 8.3144598 295 0.0056220344.0095 0.247423 28 0.157417 32 0.179905 25 172368.93 100 0.00018.3144598 295 0.00702753 44.0095 0.309278 28 0.196771 32 0.224881 30206842.72 100 0.0001 8.3144598 295 0.00843304 44.0095 0.371134 280.236125 32 0.269857 35 241316.50 100 0.0001 8.3144598 295 0.0098385544.0095 0.43299 28 0.275479 32 0.314834 40 275790.29 100 0.00018.3144598 295 0.01124405 44.0095 0.494845 28 0.314834 32 0.35981 45310264.08 100 0.0001 8.3144598 295 0.01264956 44.0095 0.556701 280.354188 32 0.404786 50 344737.86 100 0.0001 8.3144598 295 0.0140550744.0095 0.618556 28 0.393542 32 0.449762 55 379211.65 100 0.00018.3144598 295 0.01546057 44.0095 0.680412 28 0.432896 32 0.494738 60413685.44 100 0.0001 8.3144598 295 0.01686608 44.0095 0.742268 280.47225 32 0.539715 65 448159.22 100 0.0001 8.3144598 295 0.0182715944.0095 0.804123 28 0.511604 32 0.584691 70 482633.01 100 0.00018.3144598 295 0.01967709 44.0095 0.865979 28 0.550959 32 0.629667 75517106.80 100 0.0001 8.3144598 295 0.02108260 44.0095 0.927835 280.590313 32 0.674643

As noted above, the internal volume that the pressurized fluid isintended to fill can vary between implementation as well. For example,as noted above, the total internal volume can vary between 10-50 cm³.When the internal volume is less than the volume as used in the abovecalculations (25 cm³), the amount of the individual chemicals can bereduced as a lesser amount of pressurized fluid may be used. Conversely,when the internal volume is greater than the volume as used in the abovecalculations, the amount of the individual chemicals can be increased asa greater amount of pressurized fluid may be used. For example, apressure source can include between 0.10 grams and 5 grams of hydrogenperoxide. Similarly, a pressure source can include between 0.50 gramsand 7.5 grams of potassium iodide.

It should be noted that the chemicals and amounts used as described inthe above examples are for exemplary purposes only. Depending upon theimplementation, the amount of pressurized fluid to be created, theamount of internal volume to fill, and the desired pressure, the typesof chemicals used and the amounts of those chemicals can be adjustedaccordingly.

Pressure Sources Using Pressurized Fluid Reservoirs Overview

As noted above, a pressure source can include a pressurized fluidreservoir as well as a mechanical mechanism for facilitating release ofa pressurized fluid contained within the fluid reservoir. The releasedpressurized fluid can be directed to, for example, a plurality ofconductive gel reservoirs for facilitating release of conductive gelstored therein.

FIGS. 5A-11B illustrate various examples of pressure sources thatincorporate a pressurized fluid reservoir, e.g., pressure sources 500(FIG. 5A), 520 (FIG. 5B), 600 (FIG. 6), 700 (FIG. 7), 800 (FIG. 8), 900(FIG. 9), 1000 (FIG. 10), and 1100 (FIG. 11). In operation, one exampleof a pressure source as described in FIGS. 5A-11 can be integrated intoa therapy electrode such as therapy electrode 200 as discussed above,e.g., replacing pressure source 240 as discussed in reference to therapyelectrode 200. A controller, such as medical device controller 120, canbe operably connected to the pressure source. The medical devicecontroller 120 can be configured to provide an electrical signal to thepressure source prior to delivery of, for example, a therapeutic shockto a patient. The electrical signal can be configured to facilitate orotherwise initiate a release of the pressurized fluid from thepressurized fluid reservoir. The pressurized fluid can then be directedthrough the fluid channel 230 to the conductive gel reservoirs 210,thereby causing release of the conductive gel stored therein.

The pressure sources as described in relation to FIGS. 5A-11 include,for example, a preloaded amount of pressurized fluid contained in asealed or otherwise isolated reservoir. In some implementations, thepressurized fluid can be one of compressed nitrogen gas or compressedcarbon dioxide gas. In some implementations, the pressurized fluid canbe one of compressed argon gas stored in a high compression pressurevessel. The design of and materials used to manufacture the reservoircan be chosen based upon the type of pressurized fluid being used, aswell as the pressure that the pressurized fluid is to be contained at.In some implementations, the reservoir can be manufactured from a metalsuch as stainless steel or aluminum. The thickness of the walls of thesealed reservoir can be sized such that the reservoir contains thepressurized fluid is designed to minimize a chance of leakage oraccidental release due to reservoir failure. For example, thepressurized fluid can be loaded into the sealed reservoir at 100 psi. Assuch, the sealed reservoir can be designed to accommodate largerinternal pressures than the 100 psi the pressurized fluid will beloaded. In some implementations, the walls of the sealed reservoir canbe sized approximately 0.0075-0.0125 inches thick. In other examples,the walls of the sealed reservoir can be sized approximately 0.005-0.25inches thick, depending upon what material is used to manufacture thewalls. For example, if a thermoplastic such as the ionomer resin isused, a thicker wall (e.g., 0.125 inches) can be used to compensate forthe lower tensile strength of the ionomer resin as compared to stainlesssteel. Conversely, if a metal such as stainless steel is used, the wallthickness can be lower (e.g., 0.0075 inches) as a result of the highertensile strength of the stainless steel as compared to a thermoplasticmaterial.

Depending upon the intended application of the pressure source, acertain pressure level of the pressurized fluid can be configured to,for example, facilitate conductive gel release in a conductive geldeployment device. In some implementations, the pressure sourcesincluding a pressurized fluid reservoir as described below can beconfigured to produce or release a pressurized fluid at approximately 15psi to 40 psi. In other examples, the pressure sources including apressurized fluid reservoir can be configured to produce or release apressurized fluid at about 35 psi. Additionally, based upon the changein volume of the space containing the pressurized fluid (as a result ofthe pressurized fluid being released from the pressurized fluidreservoir), the pressurized fluid can be stored at a higher pressurerelative to the pressure of the pressurized fluid when released. Forexample, the pressurized fluid can be stored in the pressurized fluidreservoir at approximately 75 to 200 psi. In other examples, thepressurized fluid can be stored in the pressurized fluid reservoir atabout 100 psi. In some examples, the pressurized fluid can be stored atlevels of between 200 psi to around 2000 psi. For example, pressurizedargon gas can be stored at a compressed pressure of around 1750 psi.

Additionally, the pressure sources including a pressurized fluidreservoir as described below can be designed to replace an existingpressure source on a therapy electrode. For example, the pressuresources as described in FIGS. 5A-11B can be sized to replace pressuresource 240 on therapy electrode 200 as described above. As such, thepressure sources as described in FIGS. 5A-11B can be sized such thatthey can fit into the existing space previously occupied by pressuresource 240. In one or more implementations, the various components ofthe pressure sources are sized to fit into this space.

Various mechanical release mechanisms can be used to facilitated releaseof the pressurized fluid. The individual specifics of the exampledesigns are described below in additional detail.

Pressure Source Having a Meltable Plug

FIG. 5A illustrates a pressure source 500 that can include a pressurizedfluid reservoir 502. In some implementations, the pressurized fluidreservoir can be sealed with a meltable plug 504. As described above,the pressurized fluid reservoir 502 can be made from a metal such asstainless steel. The meltable plug 504 can be a metal or epoxy resinwith a relatively low melting point as compared to the melting point ofthe material used to manufacture the pressurized fluid reservoir 502.For example, the meltable plug 504 can be made from a metal solderhaving a melting point of about 350° F. to 425° F. In someimplementations, the meltable plug can be made from a 60%/40% lead/tincombination solder having a melting point of about 375° F. In someimplementations, the meltable plug 504 can be made from an epoxy resinsuch as a fiber-reinforced polymer having a melting point of about 450°F.

An end cap 506 can be affixed to the pressurized fluid reservoir 502.The end cap 506 can be shaped such that it can include an exit port 508.The exit port 508 can be designed such that it defines a small openingrelative to the internal diameter of the pressurized fluid reservoir502, thereby limiting the internal pressure applied to the meltable plug504 by the pressurized fluid contained therein. The meltable plug 504can be inserted into the end cap 506 prior to the pressurized fluidbeing inserted into the pressurized fluid reservoir 502. The pressurizedfluid can include an amount of a pressurized liquid or gas that providesan adequate volume and pressure for facilitating release of theconductive gel once the pressurized fluid is released from thepressurized fluid reservoir 502. Similarly, the pressurized fluid can beconfigured to remain stable when compressed in the typical operatingconditions the pressure source 500 can be anticipated to be used. Forexample, the pressurized fluid can include compressed nitrogen gas.

The pressurized fluid can include any non-noxious gas. Examples arediscussed above.

Upon insertion of the pressurized fluid, the end cap 506 can be fixedlyattached to the pressurized fluid reservoir 502. Depending upon thematerial used to manufacture the end cap 506, various methods ofattachment can be used. For example, if the end cap 506 is manufacturedfrom a similar metal as the pressurized fluid reservoir 502 (e.g.,stainless steel), the end cap 506 can be attached to the pressurizedfluid reservoir 502 using a weld 510 about the circumference of thepressurized fluid reservoir 502. To avoid damage to the meltable plug504, the end cap 506 can be shaped such that the meltable plug 504 isthermally isolated from the weld 510. For example, as shown in FIG. 5A,the end cap 506 can be of a particular length (e.g., 0.25 inches to 0.75inches) such that the meltable plug 504 can be positioned linearly awayfrom the weld 510. In certain embodiments, the end cap 506 can beapproximately 0.5 inches long. As such, any heat produced when weldingthe end cap 506 to the pressurized fluid reservoir 502 does not damagethe meltable plug 504. Additionally, the end cap 506 can have aparticular inner diameter such that the meltable plug 504 is easilyinsertable as compare to other inner diameters, while still providing alarge enough opening for pressurized fluid flow. For example, the endcap 506 can have an inner diameter of approximately 0.0125 to 0.075inches. In certain implementations, the end cap 506 can have an innerdiameter of about 0.025 inches.

To facilitate release of the meltable plug 504, the pressure source 500can include a heating element. As shown in FIG. 5A, a resistive wire 512can be positioned such that heat produced by the resistive wire 512 isapplied to the meltable plug 504, thereby melting or structurallyaltering the meltable plug 504. Similar to resistive wire 312 asdescribed above, the resistive wire 512 can be constructed from amaterial that produces heat in response to an applied current. Forexample, the resistive wire 512 can be made from nickel chromium. Thethickness of the resistive wire 512 can be selected such that thetemperature of the wire, when an appropriate current is applied, exceedsthe melting point of the meltable plug 504. For example, a 20-gauge to a28-gauge wire can be used, the wire configured to heat to approximately350° F. to 450° F. In certain implementations, a 24-gauge nickelchromium wire having a 0.020-inch diameter can heat to 400° F. atrelatively low amperages as compared to a similarly sized copper wire.

The pressurized fluid contained within the pressurized fluid reservoir502 can push a liquefied meltable plug 504 out of the exit port 508. Thepressurized fluid can flow freely from the pressurized fluid reservoir502 through, for example, a fluid channel coupled to the exit port 508and to one or more conductive gel reservoirs.

The pressure source 500 can also include a catch structure to catch anydebris that could be ejected when the meltable plug 504 is liquefied andpushed out of the exit port 508. The catch structure can also beconfigured to provide support for the resistive wire 512.

In operation, the pressure source 500 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 500 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 500.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 500 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the resistive wire 512, thereby heating the resistive wire512. Once heated, the resistive wire 512 can melt the meltable plug 504.The pressurized fluid contained within the pressurized fluid reservoir502 can push the meltable plug 504 out of the exit port 508, resultingin flow of the pressurized fluid out of the pressurized fluid reservoir502. The pressurized fluid flows through the fluid channel 230 to eachof the conductive gel reservoirs 210. The pressurized fluid can causerelease of the conductive gel contained within the conductive gelreservoirs 210, resulting in the conductive gel flowing through theapertures in the electrically conductive layer that is proximate thepatient's body. The medical device controller 120 can then facilitatedelivery of the therapeutic shock.

Depending upon the resistance of the resistive wire 512, and desiredtiming for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to heat the resistive wire 512)at the appropriate time (e.g., providing for adequate timing for thepressurized fluid release and for the subsequent release of theconductive gel). In some implementations, the pressure source 500 canalso include a localized power source that, in response to the signalfrom the medical device controller 120, is configured to provide acurrent to the resistive wire 512, thereby heating the resistive wire512 and liquefying the meltable plug 504.

FIG. 5B illustrates a pressure source 520 that can include a pressurizedfluid reservoir 522 that can be sealed with a meltable plug 524, similarto that as described in FIG. 5A. However, as shown in FIG. 5B, the shapeand design of an end cap 526 can be reversed (as compared to pressuresource 500) such that a meltable plug 524 is contained within thepressurized fluid reservoir 522.

In some implementations, the pressurized fluid reservoir 522 can be madefrom a metal such as stainless steel. The meltable plug 524 can be ametal or epoxy resin with a relatively low melting point as compared tothe melting point of the material used to manufacture the pressurizedfluid reservoir 522. For example, the meltable plug 524 can be made froma metal solder having a melting point of about 350° F. to 425° F. Insome implementations, the meltable plug can be made from a 60%/40%lead/tin combination solder having a melting point of about 375° F. Insome implementations, the meltable plug 524 can be made from an epoxyresin such as a fiber-reinforced polymer having a melting point of about450° F.

An end cap 526 can be affixed to the pressurized fluid reservoir 522.The end cap 526 can be shaped such that it can include an exit port 528.The meltable plug 524 can be inserted into the end cap 526 prior to thepressurized fluid being inserted into the pressurized fluid reservoir522. The pressurized fluid can include an amount of a pressurized liquidor gas that provides an adequate volume and pressure for facilitatingrelease of the conductive gel once the pressurized fluid is releasedfrom the pressurized fluid reservoir 522. Similarly, the pressurizedfluid can be configured to remain stable when compressed in anyconditions the pressure source 520 can be used. For example, thepressurized fluid can include compressed nitrogen gas.

Upon insertion of the pressurized fluid, the end cap 526 can be fixedlyattached to the pressurized fluid reservoir 522. Depending upon thematerial used to manufacture the end cap 526, various methods ofattachment can be used. For example, if the end cap 506 is manufacturedfrom a similar metal as the pressurized fluid reservoir 522 (e.g.,stainless steel), the end cap 526 can be attached to the pressurizedfluid reservoir 522 using a weld about the circumference of thepressurized fluid reservoir 522. To avoid damage to the meltable plug524, the end cap 526 can be shaped such that the meltable plug 524 isthermally isolated from the weld. As such, any heat produced whenwelding the end cap 526 to the pressurized fluid reservoir 522 does notdamage the meltable plug 524.

To facilitate release of the meltable plug 524, the pressure source 520can include a heating element. As shown in FIG. 5B, a resistive wire 530can be positioned such that heat produced by the resistive wire 530 isapplied to the meltable plug 524, thereby melting or structurallyaltering the meltable plug 524. Depending upon the material used tomanufacture the pressurized fluid reservoir 522, the resistive wire 530can be electrically connected to the pressurized fluid reservoir 522. Insuch a configuration, the pressurized fluid reservoir can also include aground wire 532. Thus, current applied to the resistive wire 530 canflow through the resistive wire 530, heating the resistive wire to meltthe meltable plug 524. The current can continue to flow through thepressurized fluid reservoir 522 to the ground wire 532. Additionally,the meltable plug 524, if made from, for example, an epoxy resin, can beconfigured to hold and insulate the resistive wire 530 from thepressurized fluid reservoir 522.

Similar to resistive wire 312 as described above, the resistive wire 530can be constructed from a material that produces heat in response to anapplied current. For example, the resistive wire 530 can be made fromnickel chromium. The thickness of the resistive wire 530 can be selectedsuch that the temperature of the wire, when an appropriate current isapplied, exceeds the melting point of the meltable plug 524. Forexample, a 24-gauge nickel chromium wire having a 0.020-inch diametercan heat to 400° F. at relatively low amperages as compared to a similarcopper wire.

The pressurized fluid contained within the pressurized fluid reservoir522 can push a liquefied meltable plug 524 out of the exit port 528. Thepressurized fluid can flow freely from the pressurized fluid reservoir522 through, for example, a fluid channel coupled to the exit port 528and to one or more conductive gel reservoirs.

The pressure source 520 can also include a catch structure to catch anydebris that could be ejected when the meltable plug 524 is liquefied andpushed out of the exit port 528. The catch structure can also beconfigured to provide support for the resistive wire 530.

In operation, the pressure source 520 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 520 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 520.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 520 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the resistive wire 530, thereby heating the resistive wire530. Once heated, the resistive wire 530 can melt the meltable plug 524.The pressurized fluid contained within the pressurized fluid reservoir522 can push the meltable plug 524 out of the exit port 528, resultingin flow of the pressurized fluid out of the pressurized fluid reservoir522. The pressurized fluid flows through the fluid channel 230 to eachof the conductive gel reservoirs 210. The pressurized fluid can causerelease of the conductive gel contained within the conductive gelreservoirs 210, resulting in the conductive gel flowing through theapertures in the electrically conductive layer that is proximate thepatient's body. The medical device controller 120 can then facilitatedelivery of the therapeutic shock.

Depending upon the resistance of the resistive wire 530, and desiredtiming for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to heat the resistive wire 530)at the appropriate time (e.g., providing for adequate timing for thepressurized fluid release and for the subsequent release of theconductive gel). In some implementations, the pressure source 520 canalso include a localized power source that, in response to the signalfrom the medical device controller 120, is configured to provide acurrent to the resistive wire 530, thereby heating the resistive wire530 and liquefying the meltable plug 524.

Pressure Source Having a Spring-Force Retaining Element

FIG. 6 illustrates a pressure source 600 that can include a pressurizedfluid reservoir 602 sealed with a pierceable end 604 such as a rupturedisk. As described above, the pressurized fluid reservoir 602 can bemade from a metal such as stainless steel. The pierceable end 604 can bemade from a thinner metal such as stainless steel foil that issusceptible to piercing when a sharp object is pressed against it at apredetermined pressure. As shown in FIG. 6, a puncturing pin 606 can bepositioned substantially proximate the pierceable end 604 (as shown inthe top image of FIG. 6). After movement of the pressurized fluidreservoir 602 (as shown in the bottom image of FIG. 6), the puncturingpin 606 can pierced the pierceable end 604 of the pressurized fluidreservoir 602, thereby releasing the pressurized fluid containedtherein. In certain implementations, the puncturing pin 606 can behollow or otherwise fluted to direct flow of the released pressurizedfluid to an exit port 608.

To facilitate movement of the pressurized fluid reservoir 602, a springassembly can be integrated into the pressure source 600. The top imageof FIG. 6 illustrates the spring assembly in a set and retainedposition, while the bottom image of FIG. 6 illustrates the springassembly in a released position. The spring assembly can include aspring 610 that is designed and configured to apply an outward springforce. In certain implementations, the spring 610 can be configured toexert a force of about 0.5N to 1.0N. For example, the spring 610 can beconfigured to exert a force of about 0.75N. In certain implementations,the spring 610 can be positioned against a retaining ring 612 as well asa pushing assembly 613. The retaining ring 612 can be positioned toabsorb the spring force applied to it by the spring 610 without movingrelative to the other components in the pressure source 600. As such,the retaining ring 612 can be configured to provide a stable baseagainst which the spring 610 can exert its spring force. The pushingassembly 613 can be positioned on the opposite end of the spring 610from the retaining ring 612. The pushing assembly 613 can be positionedadjacent to (or substantially adjacent to) the end of the pressurizedfluid reservoir 602 opposite the pierceable end 604. The spring 610 canbe compressed and held in the compressed position (as shown in the topimage of FIG. 6) by a retaining device 614.

The retaining device 614 can be designed to release at an appropriatetime to facilitate release of the pressurized fluid from the pressurizedfluid reservoir 602. For example, the retaining device 614 can beconstructed from a material that is designed to release the spring 610in response to one or more applied conditions. In certainimplementations, the retaining device 614 can be manufactured from athermoplastic such as polyethylene. In order to release the spring 610,the retaining device 614 can be caused to release by, for example,melting the retaining device 614. To facilitate melting of the retainingdevice 614, a resistive wire 616 can be positioned such that heatproduced by the resistive wire 616 can be applied to the retainingdevice 614, thereby melting or structurally weakening the retainingdevice 614. Once the retaining device 614 is melted or structurallyweakened, the spring 610 can be release to extend to its relaxed state(as shown in the lower image of FIG. 6). Similar to resistive wire 312as described above, the resistive wire 616 can be constructed from amaterial that produces heat in response to an applied current. Forexample, the resistive wire 616 can be made from nickel chromium havingan appropriate thickness to generate enough heat to melt the retainingdevice 614.

In some examples, to prevent accidental release of the pressurized fluid(e.g., from the pressurized fluid reservoir 602 accidentally slidinginto contact with the puncturing pin 606), the pressure source 600 caninclude a foam disc 618 that can be configured and positioned to preventmovement of the pressurized fluid reservoir 602 under normal operatingconditions. In certain implementations, upon release of the spring 610(e.g., from the release of the retaining device 614), the foam disc 618can be compressed (as shown in the lower image of FIG. 6). Thus, thefoam disc 618 can be positioned within the pressure source 600 such thatit does not prevent operation of the pressure source 600. In someexamples, in order to be compressed by the spring 610, the foam disc 618can be manufactured from an open cell foam such as open cellpolyurethane foam.

In certain implementations, the pressure source 600 can include anO-ring 620 positioned to prevent backflow of the pressurized fluid whenreleased from the pressurized fluid reservoir 602. As shown in FIG. 6,the O-ring 620 can be positioned around the pressurized fluid reservoir602 to prevent backflow while not restricting movement of thepressurized fluid reservoir 602 during operation of the pressure source600. In certain implementations, the O-ring 620 can be made from athermoplastic elastomer such as synthetic rubber.

In operation, the pressure source 600 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 600 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 600.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 600 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the resistive wire 616, thereby heating the resistive wire616. Once heated, the resistive wire 616 can melt or otherwise weakenthe retaining device 614. The weakened retaining device 614 can split orotherwise break, causing release of the spring 610. The spring 610, asit returns to its resting position, can exert a spring force on thepushing assembly 613, thereby facilitating movement of the pressurizedfluid reservoir 602. The pressurized fluid reservoir 602 can compressthe foam disc 618 and contact the puncturing pin 606. The puncturing pin606 can puncture the pierceable end 604 of the pressurized fluidreservoir 602, resulting in release of the pressurized fluid containedtherein. The pressurized fluid can flow into the exit port 608, whilethe O-ring 620 can prevent backflow of the pressurized fluid. Thepressurized fluid can flow through exit port 608 into the fluid channel230 and to each of the conductive gel reservoirs 210. The pressurizedfluid can cause release of the conductive gel contained within theconductive gel reservoirs 210, resulting in the conductive gel flowingthrough the apertures in the electrically conductive layer that isproximate the patient's body. The medical device controller 120 can thenfacilitate delivery of the therapeutic shock.

Depending upon the resistance of the resistive wire 616, and desiredtiming for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to heat the resistive wire 616 tomelt the retaining device 614) at the appropriate time (e.g., providingfor adequate timing for the release of the pressurized fluid and for thesubsequent release of the conductive gel). In some implementations, thepressure source 600 can also include a localized power source that, inresponse to the signal from the medical device controller 120, can beconfigured to provide a current to the resistive wire 616, therebyheating the resistive wire 616 and melting the retaining device 614.

Pressure Source Having a Sliding Valve

FIGS. 7A and 7B illustrate a pressure source 700 that can include ahousing 702. The housing 702 can be configured to both house an amountof a pressurized fluid in one end and various components forfacilitating release of the pressurized fluid. FIG. 7A illustrates asample top cross-sectional view, while FIG. 7B illustrates a sample sidecross-sectional view of pressure source 700.

The housing 702 can be formed from a material that is strong enough towithstand the pressure exerted by the pressurized fluid containedtherein. For example, the housing 702 can be made from a metal such asstainless steel or aluminum. The metal can be stamped, rolled, orsimilarly formed to contain the pressurized fluid and other componentsrelated to facilitating release of the pressurized fluid. In anotherexample, the housing 702 can be formed from a thermoplastic plastic suchas polyethylene. The plastic can be formed by a thermoforming process,an injection molding process, or other similar forming process.

The housing 702 can include a pressurized fluid reservoir 704 configuredto contain an amount of a pressurized fluid. The pressurized fluidreservoir 704 can be connected to an internal fluid conduit 706 suchthat the pressurized fluid can flow through the internal fluid conduit706. A sliding valve 708 can be positioned substantially adjacent to anend of the internal fluid conduit 706 opposite the pressurized fluidreservoir 704. In certain implementations, the sliding valve 708 can beconfigured to slide such that it moves from a closed position to an openposition. When in the closed position, the sliding valve 708 caninterrupt a fluid connection between the fluid conduit 706 and an exitport 710. When in the open position, the sliding valve 708 can move to aposition where the fluid conduit 706 and the exit port 710 are in fluidcommunication. Thus, in certain implementations, when the sliding valve708 is in the open position, the exit port 710 and the internal fluidconduit 706 can form a fluid pathway for flow of the pressurized fluidout of the pressurized fluid reservoir 704. Conversely, when the slidingvalve 708 is in the closed position, the fluid pathway can be broken andthe pressurized fluid can remain contained within the pressurized fluidreservoir 704.

To facilitate movement of the sliding valve 708, the sliding valve 708can be connected to a movement causing device such as solenoid 712. Thesolenoid 712 can be positioned and configured to either push or pull thesliding valve 708. For example, in response to an electrical signal froma controller, the solenoid 712 can apply a pulling force to the slidingvalve 708, resulting in the sliding valve 708 moving to the openposition such that the exit port 710 is in fluid communication with theinternal fluid conduit 706.

The sliding valve 708 can also include one or more O-rings 714positioned to prevent backflow (or misdirected flow) of the pressurizedfluid as well as to stabilize and secure the moving components of thesliding valve 708 within the housing 702. In certain implementations,the O-rings 714 can be made from a thermoplastic elastomer such assynthetic rubber.

The pressure source 700 can also include a pressure sensor 716. Thepressure sensor 716 can be configured to monitor the internal pressureof the pressurized fluid reservoir 704. The pressure sensor 716 can beoperably connected to, for example, a controller such as medical devicecontroller 120. The medical device controller 120 can monitor thepressure of the pressurized fluid contained within pressure source 700and provide an indication of any potential malfunctions (e.g., if thepressure falls below a set threshold).

In operation, the pressure source 700 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 700 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 700.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 700 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the solenoid 712. The solenoid 712 can move the slidingvalve 708, thereby establishing a fluid connection between the exit port710 and the pressurized fluid reservoir 704 (via the fluid conduit 706).The pressurized fluid can flow from the pressurized fluid reservoir 704to the exit port 710. The pressurized fluid can flow through the fluidchannel 230 to each of the conductive gel reservoirs 210. Thepressurized fluid can cause release of the conductive gel containedwithin the conductive gel reservoirs 210, resulting in the conductivegel flowing through the apertures in the electrically conductive layerthat is proximate the patient's body. The medical device controller 120can then facilitate delivery of the therapeutic shock.

Depending upon the electrical requirements of the solenoid 712, anddesired timing for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to move the solenoid 712) at theappropriate time (e.g., providing for adequate timing for the release ofthe pressurized fluid and for the subsequent release of the conductivegel). In some implementations, the pressure source 700 can also includea localized power source that, in response to the signal from themedical device controller 120, is configured to provide a current to thesolenoid 712, thereby facilitating movement of the solenoid 712 and thesliding valve 708.

Additionally, in certain implementations, the pressure source 700 can bedesigned to be refillable. For example, the sliding valve 708 can bemoved to the open position. The pressurized fluid reservoir 704 can befilled with a pressurized fluid injected through the exit port. Incertain implementations, the pressure sensor 716 can provide anindication that the internal pressure of the pressurized fluid reservoir704 has reached a certain point, indicating that the pressurized fluidreservoir 704 is at maximum capacity (determined, for example, basedupon the internal volume of the pressurized fluid reservoir 704 and theassociated pressure the housing 702 is configured to tolerate). Thesolenoid 712 can slide the sliding valve 708 into the closed positionsuch that the fluid connection between the exit port 710 and theinternal fluid conduit 706 is broken, thereby containing the pressurizedfluid within the pressurized fluid reservoir 704.

Pressure Source Having an Actuating Lever

FIG. 8 illustrates a pressure source 800 that can include a pressurizedfluid reservoir 802 sealed with a pierceable end. As described above,the pressurized fluid reservoir 802 can be made from a metal such asstainless steel. The pierceable end can be made from a thinner metalsuch as stainless steel foil that is susceptible to piercing when asharp object is pressed against it. As shown in FIG. 8, a puncturing pin804 can be positioned proximate the pierceable end of the pressurizedfluid reservoir 802. In certain implementations, the puncturing pin 804can be configured to move such that the puncturing pin 804 pierces thepierceable end of the pressurized fluid reservoir 802. Upon release ofthe pressurized fluid from the pressurized fluid reservoir 802, thefluid can be directed to an exit port 806 of the pressure source 800.

To facilitate movement of the puncturing pin 804, an actuating leverassembly can be integrated into the pressure source 800. For example, asshown in FIG. 8, the pressure source 800 can include an actuating lever808. In certain implementations, the actuating lever 808 can be orientedsuch that the actuating lever 808 runs parallel to the pressurized fluidreservoir 802. The actuating lever 808 can be manufactured from amaterial such as aluminum, carbon fiber, or various thermoplastics suchas polystyrene. The actuating lever 808 can be configured to pivot abouta fulcrum point 810, thereby causing movement of the puncturing pin 804.For example, a vertical movement of the actuating lever 808 can betransferred to the puncturing pin 804 as a horizontal force as a resultof the 90° bend in the actuating lever 808 and movement of the actuatinglever 808 about the fulcrum point 810.

The pressure source 800 can include a spring 812 that can be configuredto facilitate movement of the actuating lever 808. In certainimplementations, the spring 812 can be configured to exert an outwardlydirected spring force. As such, the spring 812 can be compressed asshown in FIG. 8, thereby resulting in the spring 812 storing theoutwardly directed spring force until the spring is released. A releasemechanism 814 can be configured to hold the spring 812 in its compressedstate until a signal is provided to release the spring 812. The releasemechanism 814 can include, for example, a ball screw in combination witha solenoid or other similar motor configured to hold the spring 812 inits compressed state. In certain implementations, upon receiving asignal to release the spring 812, the release mechanism 814 can releasethe spring 812 from its compressed state. The spring 812 can exert itsoutwardly directed spring force on the actuating lever 808. Theactuating lever 808 can move vertically which, as described above, canbe translated to a horizontal movement of the puncturing pin 804.

In operation, the pressure source 800 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 800 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 800.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 800 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the release mechanism 814. In response to the electricalsignal, the release mechanism 814 can release the spring 812. The spring812 can exert a vertical force on the actuating lever 808. The actuatinglever 808 can pivot around the fulcrum point 810, transferring ahorizontal pushing force to the puncturing pin 804. The puncturing pin804 can pierce the pierceable end of the pressurized fluid reservoir802, resulting in release of the pressurized fluid contained therein.The pressurized fluid can flow through exit port 806 into the fluidchannel 230 and to each of the conductive gel reservoirs 210. Thepressurized fluid can cause release of the conductive gel containedwithin the conductive gel reservoirs 210, resulting in the conductivegel flowing through the apertures in the electrically conductive layerthat is proximate the patient's body. The medical device controller 120can then facilitate delivery of the therapeutic shock.

Depending upon the electrical requirements of the release mechanism 814,and desired timing for the release of the conductive gel, the medicaldevice controller 120 can be configured to deliver an appropriateelectrical signal (e.g., at a high enough current to operate the releasemechanism 814) at the appropriate time (e.g., providing for adequatetiming for the release of the pressurized fluid and for the subsequentrelease of the conductive gel). In some implementations, the pressuresource 800 can also include a localized power source that, in responseto the signal from the medical device controller 120, is configured toprovide a current to the release mechanism 814, thereby facilitatingrelease of the spring 812.

Pressure Source Having a Fusible Alloy Release

FIG. 9 illustrates a pressure source 900 that can include a body 902.The body 902 can be configured to house both an amount of a pressurizedfluid in one end and various components for facilitating release of thepressurized fluid in an opposite end. The body 902 can be formed from,for example, a metal such as stainless steel or aluminum. The body 902can include two separate bore sizes, a smaller bore at one end forcontainment of the pressurized fluid (the smaller bore results inthicker walls, thereby increasing the pressure of the fluid that can becontained therein) and a larger bore in the opposite end for containmentof the various components. In certain implementations, the smaller borecan result in walls having a thickness of approximately 0.0075 inchesthick and the larger bore can result in walls having a thickness ofapproximately 0.0025 inches thick.

As shown in FIG. 9, the body 902 can include a pressurized fluidreservoir 904 located in the smaller bored end of the body 902. The body902 can also include one or more exit ports 906 for directing thepressurized fluid to, for example, a fluid channel for facilitatingconductive gel release as described above. A piston 908 can bepositioned within the body 902 that is positioned and configured toprevent the pressurized fluid from flowing from the pressurized fluidreservoir 904 to the exit ports 906 at unwanted times.

The pressure source 900 can include various components for facilitatingrelease of the pressurized fluid from the pressurized fluid reservoir904. In some implementations, the pressure source can include a spring910 that can be configured to apply a spring force against the piston908 to aid in unwanted movement of the piston 908. Additionally, ameltable alloy plug 912 can be positioned within the body 902 to opposemovement of the piston 908. In certain implementations, the pressurizedfluid can exert a first force on the piston 908 in a first direction(e.g., to the left of FIG. 9). The combination of the spring 910 and themeltable alloy plug 912 can provide a second force on the piston 908 ina second direction opposite to the first force (e.g., to the right ofFIG. 9) and essentially equal in magnitude to the first force. Incertain implementations, the first force and the second force can beapproximately 1 N.

In some examples, the piston 908 can remain motionless as the two forcesare balanced. In order to facilitate movement of the piston 908, themeltable alloy plug 912 can be designed to release or otherwise ceaseopposing movement of the piston 908 at an appropriate time. A resistivewire 914 can be, for example, inserted through holes in a threaded endcap 916 and wrapped around the meltable alloy plug 912. In certainimplementations, the meltable alloy plug 912 can be a metal solderhaving a relatively low melting point. For example, the meltable alloyplug 912 can be made from a lead/tin combination solder having a meltingpoint of about 375° F. Similar to resistive wire 312 as described above,the resistive wire 914 can be constructed from a material that producesheat in response to an applied current. For example, the resistive wire914 can be made from nickel chromium. The thickness of the resistivewire 914 can be selected such that the temperature of the wire, when anappropriate current is applied, exceeds the melting point of themeltable alloy plug 912. For example, a 24-gauge nickel chromium wirehaving a 0.020-inch diameter can heat to 400° F. at relatively lowamperages as compared to a similar copper wire.

In certain implementations, the resistive wire 914 can be configured tomelt the meltable alloy plug 912. In some examples, the force exerted onthe piston 908 by the pressurized fluid can exceed the pressure exertedon the piston solely by the spring 910. As such, the pressurized fluidcan push the piston 908, thereby exposing the exit ports 906 andestablishing a fluid connection between the pressurized fluid reservoir904 and the exit ports 906. The pressurized fluid can flow from thepressurized fluid reservoir 904 into the exit ports 906.

The piston 908 can also include one or more O-rings 918 positioned toprevent leakage of the pressurized fluid from the pressurized fluidreservoir 904. In some implementations, the O-rings 918 can be made froma thermoplastic elastomer such as synthetic rubber. The O-rings 918 canalso be sized to produce a friction fit between the piston 908 and thebody 902.

In operation, the pressure source 900 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 900 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 900.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 900 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the resistive wire 914, thereby heating the resistive wire914. Once heated, the resistive wire 914 can melt the meltable alloyplug 912, which results in movement of the piston 908. As noted above,upon melting of the meltable alloy plug 912, the pressure exerted on thepiston 908 by the pressurized fluid can result in movement of the piston908. After movement of the piston 908, the pressurized fluid can flowinto the exit ports 906. The pressurized fluid can flow through exitports 906 into the fluid channel 230 and to each of the conductive gelreservoirs 210. The pressurized fluid can cause release of theconductive gel contained within the conductive gel reservoirs 210,resulting in the conductive gel flowing through the apertures in theelectrically conductive layer that is proximate the patient's body. Themedical device controller 120 can then facilitate delivery of thetherapeutic shock.

Depending upon the resistance of the resistive wire 914, and desiredtiming for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to heat the resistive wire 914 tomelt the meltable alloy plug 912) at the appropriate time (e.g.,providing for adequate timing for the pressurized fluid release and forthe subsequent release of the conductive gel). In some examples, thepressure source 900 can also include a localized power source that, inresponse to the signal from the medical device controller 120, isconfigured to provide a current to the resistive wire 914, therebyheating the resistive wire 914 and melting the meltable alloy plug 912.

Pressure Source Having a Micro Drill

FIG. 10 illustrates a pressure source 1000 that includes a pressurizedfluid reservoir 1002. As described above, the pressurized fluidreservoir 1002 can be made from a metal such as stainless steel. Asshown in FIG. 10, a micro drill bit 1008 can be positioned proximate anend of the pressurized fluid reservoir 1002. In certain implementations,the micro drill bit 1008 can be a hardened steel drill bit having adiameter of approximately 0.02 inches. A spring 1006 can be positionedat an end of the pressurized fluid reservoir 1002 that is opposite themicro drill bit 1008. The spring 1006 can be configured to exert a smallforce (e.g., 0.5 N) on the pressurized fluid reservoir 1002, therebyholding the pressurized fluid reservoir 1002 against the micro drill bit1008. However, the force exerted on the pressurized fluid reservoir 1002by the spring 1006 can be configured to not move push the pressurizedfluid reservoir 1002 against the micro drill bit 1008 with such forcethat the micro drill bit 1008 can puncture the pressurized fluidreservoir 1002 prior to activation of the micro drill bit 1008 (e.g.,such that the movement of the micro drill bit 1008 results in punctureof the pressurized fluid reservoir, not the spring force exerted byspring 1006).

A motor 1010 can be operably connected to the micro drill bit 1008 tocause rotational motion of the micro drill bit 1008. In certainimplementations, the motor 1010 can be a planetary gear motor configuredto accept the micro drill bit 1008. Upon application of an electricalsignal to the motor 1010, the motor 1010 can be configured to transfer arotation motion to the micro drill bit 1008, causing the micro drill bit1008 to spin in, for example, a clockwise direction. In certainimplementations, the rotational motion of the micro drill bit 1008, incombination with the spring force applied by the spring 1006, can causethe micro drill bit 1008 to drill a hole into the pressurized fluidreservoir 1002. The pressurized fluid contained within the pressurizedfluid reservoir 1002 can flow out of the pressurized fluid reservoir1002 and through an exit port 1004.

In operation, the pressure source 1000 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 1000 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 1000.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 1000 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the motor 1010. In response to the electrical signal, themotor 1010 can apply a rotational motion to the micro drill bit 1008.The spring 1006 can exert a force on the pressurized fluid reservoir1002, thereby pushing the pressurized fluid reservoir 1002 against thespinning micro drill bit 1008. The rotating micro drill bit 1008 canpuncture the pressurized fluid reservoir 1002, thereby releasingpressurized fluid contained therein. The pressurized fluid can flowthrough exit port 1004 into the fluid channel 230 and to each of theconductive gel reservoirs 210. The pressurized fluid can cause releaseof the conductive gel contained within the conductive gel reservoirs210, resulting in the conductive gel flowing through the apertures inthe electrically conductive layer that is proximate the patient's body.The medical device controller 120 can then facilitate delivery of thetherapeutic shock.

Depending upon the electrical requirements of the motor 1010, anddesired timing for the release of the conductive gel, the medical devicecontroller 120 can be configured to deliver an appropriate electricalsignal (e.g., at a high enough current to operate the motor 1010) at theappropriate time (e.g., providing for adequate timing for thepressurized fluid release and for the subsequent release of theconductive gel). In some examples, the pressure source 1000 can alsoinclude a localized power source that, in response to the signal fromthe medical device controller 120, is configured to provide a current tothe motor 1010, thereby rotating the micro drill bit 1008 for drillinginto the pressurized fluid reservoir 1002.

Pressure Source Having an Expanding Release Mechanism

FIGS. 11A and 11B illustrate a pressure source 1100 that includes apressurized fluid reservoir 1102. As described above, the pressurizedfluid reservoir 1102 can be made from a metal such as stainless steel.FIG. 11A shows an exploded view of the pressure source 1100, while FIG.11B shows an assembled view of the pressure source 1100. Unlessspecifically noted, both FIGS. 11A and 11B will be describedsimultaneously in the following description.

A puncturing pin 1104 can be positioned proximate an end of thepressurized fluid reservoir 1102. For example, the puncturing pin 1104can be a hardened steel pin configured to pierce a pierceable end of thepressurized fluid reservoir 1102. An expanding release mechanism 1106can be operably attached to the puncturing pin 1104. The expandingrelease mechanism 1106 can be configured to expand in response tocertain stimulus. For example, the expanding release mechanism 1106 canbe a wax motor that is configured to expand upon application of heat tothe wax. In operation, a wax motor can be constructed to include a waxthat expands as it melts. In certain implementations, a wax motor caninclude a wax configured to expand when melted, the wax having a meltingpoint of approximately 125° F. to 175° F. For example, the wax motor caninclude a paraffin wax configured to melt at about 150° F. As the waxmelts, the expansion of the wax can be used to apply a pushing force toanother object such as the puncturing pin 1104.

As shown in FIG. 11B, a heating element such as resistive wire 1108 canbe wrapped around or embedded in a wax motor (if used, for example, asthe expanding release mechanism 1106) to melt the wax contained withinthe wax motor. Similar to resistive wire 312 as described above, theresistive wire 1108 can be constructed from a material that producesheat in response to an applied current. For example, the resistive wire1108 can be made from nickel chromium. The thickness of the resistivewire 1108 can be selected such that the temperature of the wire, when anappropriate current is applied, exceeds the melting point of the waxused in manufacture of the wax motor (if used, for example, as theexpanding release mechanism 1106). For example, a 24-gauge nickelchromium wire having a 0.020-inch diameter can heat to 400° F. atrelatively low amperages as compared to a similar copper wire.

Upon expansion of the wax, the puncturing pin 1104 can puncture thepressurized fluid reservoir 1102, thereby resulting in release of thepressurized fluid contained therein. The pressurized fluid can bedirected to one or more exit ports for delivery to one or moreconductive gel reservoirs to facilitate release of the conductive gel.

In operation, the pressure source 1100 can be integrated into a therapyelectrode such as therapy electrode 200 as discussed above. For example,the pressure source 1100 can replace pressure source 240 as discussed inreference to therapy electrode 200. A controller, such as medical devicecontroller 120, can be operably connected to the pressure source 1100.The medical device controller 120 can be configured to provide anelectrical signal to the pressure source 1100 prior to delivery of, forexample, a therapeutic shock to a patient. The electrical signal can bedirected to the expanding release mechanism 1106. For example, if a waxmotor is used, the electrical signal can be directed to the resistivewire 1108. The resistive wire 1108 can heat the wax contained in the waxmotor, resulting in expansion of the wax. The expansion of the wax canexert a pushing force on the puncturing pin 1104. The puncturing pin1104 can puncture the pressurized fluid reservoir 1102, therebyreleasing the pressurized fluid contained therein. The pressurized fluidcan flow through one or more exit ports, into the fluid channel 230 andto each of the conductive gel reservoirs 210. The pressurized fluid cancause release of the conductive gel contained within the conductive gelreservoirs 210, resulting in the conductive gel flowing through theapertures in the electrically conductive layer that is proximate thepatient's body. The medical device controller 120 can then facilitatedelivery of the therapeutic shock.

Depending upon the electrical requirements of the expanding releasemechanism 1106, and desired timing for the release of the conductivegel, the medical device controller 120 can be configured to deliver anappropriate electrical signal (e.g., at a high enough current to causeexpansion of the expanding release mechanism 1106) at the appropriatetime (e.g., providing for adequate timing for the pressurized fluidrelease and for the subsequent release of the conductive gel). In someimplementations, the pressure source 1100 can also include a localizedpower source that, in response to the signal from the medical devicecontroller 120, is configured to provide a current to the expandingrelease mechanism.

Use of Gel Deployment with an Ambulatory Medical Device

FIG. 12 depicts an example of conductive gel entering the area between atherapy electrode and the subject's skin after being released by, forexample, a gel deployment devices including one of the pressure sourcesas described above (e.g., pressure sources 300, 400, 500, 520, 600, 700,800, 900, 1000 and 1100 as shown in FIGS. 3, 4, 5A, 5B, 6, 7, 8, 9, 10,11A and 11B). In one implementation, after release from a gel deploymentdevice, the conductive gel can enter the area between a conductivesurface 1205 of therapy electrode 1200 and the subject's skin, and canform a conduction path 1210 from the therapy electrode 1200 to thesubject's skin. The conductive gel can cover conductive thread or meshfabric 1215 that is part of a garment (e.g., garment 110), portions ofwhich can be disposed between the subject's skin and the therapyelectrode 1200. For example, the gel deployment device can be configuredin a form of a removable receptacle. As such, after the pressure sourceis used and the gel is deployed, the gel deployment device can beremoved and replaced.

FIG. 13 illustrates components of external medical device 1300 accordingto certain implementations, with sensing electrodes 1350 including atleast one EKG (or ECG) electrocardiogram sensor, conductive thread 1305woven into belt 1310 of garment 110, and gel deployment device 1345disposed proximate to a first therapy electrode 1335 in garment 110.

In one implementation, a control unit 1350 can instruct the geldeployment device 1345 to release the conductive gel included inconductive gel reservoir 1355. The released conductive gel can reduceimpedance between the subject's skin and first therapy electrode 1335.Therapy controller 1315 can apply treatment (e.g., a therapeutic shock)to the subject via first therapy electrode 1335 and second therapyelectrode 1340 (that can include another gel deployment device 1345 fordeployment of conductive gel between second therapy electrode 1340 andthe patient's skin). During treatment, current can follow a path betweenthe subject's skin and first therapy electrode 1335 and second therapyelectrode 1340 via the conductive gel.

Although the subject matter contained herein has been described indetail for the purpose of illustration, it is to be understood that suchdetail is solely for that purpose and that the present disclosure is notlimited to the disclosed embodiments, but, on the contrary, is intendedto cover modifications and equivalent arrangements that are within thespirit and scope of the appended claims. For example, it is to beunderstood that the present disclosure contemplates that, to the extentpossible, one or more features of any embodiment can be combined withone or more features of any other embodiment.

Other examples are within the scope and spirit of the description andclaims. Additionally, certain functions described above can beimplemented using software, hardware, firmware, hardwiring, orcombinations of any of these. Features implementing functions can alsobe physically located at various positions, including being distributedsuch that portions of functions are implemented at different physicallocations.

What is claimed is:
 1. An electrode for providing electrotherapy from anambulatory electrotherapy device comprising: at least one reservoircomprising a conductive gel; at least one pressure source comprising achemical reaction chamber comprising a first chemical and a secondchemical isolated from each other by a mechanical barrier, wherein themechanical barrier is configured to be compromised upon receiving asignal from an electrotherapy device controller, and wherein the firstchemical and second chemical come into contact when the mechanicalbarrier is compromised to produce a sufficient amount of pressurizedfluid to generate a sufficient pressure within the chamber.
 2. Theelectrode of claim 1, further comprising at least one release mechanismconfigured to compromise the mechanical barrier, thereby releasing thesecond chemical such that the second chemical reacts with the firstchemical.
 3. The electrode of claim 2, wherein the at least one releasemechanism comprises a heat producing device or a mechanical deviceconfigured to facilitate movement of at least one of the first chemicaland the second chemical.
 4. The electrode of claim 1, wherein themechanical barrier comprises at least one meltable membrane configuredto isolate the first chemical from the second chemical.
 5. The electrodeof claim 1, wherein the first chemical is in solid form and the secondchemical is in a liquid form, and the pressurized fluid producedcomprises at least one of carbon dioxide, nitrogen, oxygen, and mixturesthereof.
 6. The electrode of claim 1, further comprising an exit portconnected to a fluid channel, wherein the exit port is configured todirect the pressurized fluid into the fluid channel.
 7. The electrode ofclaim 1, wherein a pressure level of the produced fluid is between 15psi and 40 psi.
 8. A system for providing therapy to a patient, thesystem comprising: a garment; a monitor configured to monitor at least aphysiological parameter of a patient; and a plurality of therapyelectrodes operably connected to the monitor and disposed in thegarment, each of the plurality of therapy electrodes comprising apressure source for providing a pressurized fluid to facilitateconductive gel deployment in a wearable medical device, the pressuresource comprising a chemical reaction chamber comprising a firstchemical and a second chemical isolated from each other by a mechanicalbarrier, wherein the mechanical barrier is configured to be compromisedupon receiving a signal from an electrotherapy device controller, andwherein the first chemical and second chemical come into contact whenthe mechanical barrier is compromised to produce a sufficient amount offluid to generate a sufficient pressure within the chamber.
 9. Thesystem of claim 8, wherein each of the plurality of therapy electrodesfurther comprise at least one conductive surface configured to deliver atherapeutic shock.
 10. The system of claim 8, further comprising atleast one release mechanism configured to compromise the mechanicalbarrier, thereby releasing the second chemical such that the secondchemical reacts with the first chemical.
 11. The system of claim 10,wherein the at least one release mechanism comprises a heat producingdevice or a mechanical device configured to facilitate movement of atleast one of the first chemical and the second chemical.
 12. A pressuresource for providing a pressurized fluid to facilitate conductive geldeployment in a wearable medical device, the pressure source comprising:a reservoir containing a pressurized fluid; and at least one releasemechanism configured to cause a release of the pressurized fluid fromthe reservoir to an exit port of the pressure source when the wearablemedical device is preparing to deliver a therapeutic shock to a patient.13. The pressure source of claim 12, wherein the at least one releasemechanism comprises at least one heating element, or a piston positionedto block flow of the pressurized fluid from the reservoir to the exitport, wherein the piston is configured to slidably release thepressurized fluid to the exit port, or a movable piercing devicepositioned adjacent to a pierceable end of the reservoir.
 14. Thepressure source of claim 13, wherein the reservoir comprises a meltableplug positioned in contact with the at least one heating element andconfigured to melt upon application of a current to the at least oneheating element, thereby resulting in release of the pressurized fluidthrough the exit port.
 15. The pressure source of claim 12, wherein thepressurized fluid comprises at least one of carbon dioxide, nitrogen,oxygen, argon and mixtures thereof.
 16. The pressure source of claim 12,further comprising: a piercing device positioned adjacent to apierceable end of the reservoir; and a spring mechanism configured tofacilitate movement of at least one of the piercing device and thereservoir, thereby resulting in a piercing of the pierceable end of thereservoir and release of the pressurized fluid through the exit port.17. The pressure source of claim 16, wherein the spring mechanismcomprises a meltable retaining mechanism positioned adjacent to at leastone heating element, wherein the meltable retaining mechanism isconfigured to melt upon application of a current to the at least oneheating element, thereby resulting in the movement of at least one ofthe piercing device and the reservoir.
 18. The pressure source of claim16, wherein the piercing device comprises a drill positioned such that adrill bit is adjacent to the pierceable end of the reservoir.
 19. Thepressure source of claim 18, wherein application of a current to thedrill results in rotational movement of the drill bit such that thedrill bit penetrates the pierceable end of the reservoir.
 20. Thepressure source of claim 13, further comprising a spring mechanismconfigured to slide the piston to facilitate release of the pressurizedfluid.
 21. The pressure source of claim 20, further comprising at leastone retaining element configured to oppose a spring force exerted by thespring mechanism to prevent movement of the piston, wherein the at leastone retaining element is positioned adjacent to at least one heatingelement and is configured to melt upon application of a current to theat least one heating element, thereby resulting in movement of thepiston and release of the pressurized fluid to the exit port.
 22. Thepressure source of claim 13, wherein the moveable piercing devicecomprises a motor configured to move puncturing device through into thepierceable end of the reservoir, thereby resulting in release of thepressurized fluid.
 23. The pressure source of claim 22, wherein themotor comprises at least one of a solenoid and an expanding waxactuator.
 24. A system for providing therapy to a patient, the systemcomprising: a garment; a monitor configured to monitor at least aphysiological parameter of a patient; and a plurality of therapyelectrodes operably connected to the monitor and disposed in thegarment, each of the plurality of therapy electrodes comprising apressure source for providing a pressurized fluid to facilitateconductive gel deployment in a wearable medical device, the pressuresource comprising a reservoir containing a pressurized fluid, and atleast one release mechanism configured to cause a release of thepressurized fluid from the reservoir to an exit port of the pressuresource when the monitor is preparing to deliver a therapeutic shock to apatient.
 25. The system of claim 24, wherein each of the plurality oftherapy electrode further comprise at least one conductive surfaceconfigured to deliver the therapeutic shock.
 26. The system of claim 24,wherein the at least one release mechanism comprises: at least oneheating element and a meltable plug positioned in contact with the atleast one heating element and configured to melt upon application of acurrent to the at least one heating element, thereby resulting inrelease of the pressurized fluid through the exit port or a pistonposition to block flow of the pressurized fluid from the reservoir tothe exit port, wherein the piston is configured to slidably release thepressurized fluid to the exit port or a movable piercing devicepositioned adjacent to a pierceable end of the reservoir.
 27. The systemof claim 24, wherein the pressure source further comprises: a piercingdevice positioned adjacent to a pierceable end of the reservoir; and aspring mechanism configured to facilitate movement of at least one ofthe piercing device and the reservoir, thereby resulting in a piercingof the pierceable end of the reservoir and release of the pressurizedfluid through the exit port.
 28. A method for providing electrotherapyfrom an ambulatory electrotherapy device comprising: providing anelectrode; providing at least one reservoir comprising a conductive gel;providing at least one pressure source comprising a chemical reactionchamber comprising a first chemical and a second chemical isolated fromeach other by a mechanical barrier, wherein the mechanical barrier isconfigured to be compromised upon receiving a signal from anelectrotherapy device controller, and wherein the first chemical andsecond chemical come into contact when the mechanical barrier iscompromised to produce a sufficient amount of fluid to generate asufficient pressure within the chamber.
 29. The method of claim 28,wherein the pressure source comprises producing carbon dioxide by areaction of the first chemical and the second chemical.
 30. The methodof claim 29, wherein the first chemical is a metal carbonate orbicarbonate and the second chemical is an acid.
 31. The method of claim28, wherein the pressure source comprises producing carbon dioxide,nitrogen, oxygen, or mixtures thereof.